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Volume 2, ECCS 2020
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Chem. Proc., 2021, ECSOC-24

The 24th International Electronic Conference on Synthetic Organic Chemistry

Online | 15 November–15 December 2020

Volume Editors: Julio A. Seijas and M. Pilar Vázquez-Tato

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Cover Story (view full-size image): Electronic Conference on Synthetic Organic Chemistryis a series of conferences that have been maintained through the internet since 1997. This series is an original initiative by MDPI, later [...] Read more.
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Abstract
Magnetized Dextrin: Eco-Friendly Effective Nanocatalyst for the Synthesis of Dihydropyrano[2,3-c]pyrazole Derivatives
Chem. Proc. 2021, 3(1), 101; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08285 - 14 Nov 2020
Cited by 1 | Viewed by 152
Abstract
Dextrin is a water soluble polysaccharide obtained by hydrolysis of starch and glycogen. This low molecular weight biopolymer with valuable properties such as biodegradability, biocompatibility, good availability, and high reactivity can be an appropriate substance to fabricate the environmentally friendly catalysts. The magnetized [...] Read more.
Dextrin is a water soluble polysaccharide obtained by hydrolysis of starch and glycogen. This low molecular weight biopolymer with valuable properties such as biodegradability, biocompatibility, good availability, and high reactivity can be an appropriate substance to fabricate the environmentally friendly catalysts. The magnetized dextrin was prepared via facile co-precipitation procedure of iron salts in the presences of dextrin under alkaline condition. Then, it was characterized by different conventional analyses. Eventually, the catalytic application of obtained nanocomposite was evaluated for the synthesis dihydropyrano[2,3-c]pyrazole derivatives through multicomponent reaction of hydrazine hydrate, ethyl acetoacetate, aromatic aldehydes, and malononitrile. Biocompatible nanocatalyst, simple procedure, short reaction times, and catalyst reusability after four consecutive runs with negligible decrease in catalytic efficiency are some merits of the presented method. Full article
Abstract
Chemical Fingerprinting and Antimicrobial Evaluation of the Methanolic Extract of the Leaves of the Endemic Cuban Plant Coccoloba cowellii 
Chem. Proc. 2021, 3(1), 124; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08289 - 14 Nov 2020
Viewed by 221
Abstract
The genus Coccoloba (Polygonaceae) comprises approximately 150 species of flowering plants. It is native to the tropical and subtropical regions of America, in South America, the Caribbean and Central America. A wide variety of biological activities has been studied for Coccoloba species due [...] Read more.
The genus Coccoloba (Polygonaceae) comprises approximately 150 species of flowering plants. It is native to the tropical and subtropical regions of America, in South America, the Caribbean and Central America. A wide variety of biological activities has been studied for Coccoloba species due to great diversity of metabolites (mainly flavonoids, tannins, terpenoids and volatile oils) and popular uses reported for different ailments like fever, diarrhea, menstrual disturbance, uterine hemorrhages, hemorrhoids and gonorrhea. The methanolic extract of the leaves of C. cowellii, endemic of the Camagüey province of Cuba and critically endangered, was subjected to structural analysis. The obtained HPLC-DAD-QTOF-ESI-MS data were analyzed employing the MS-DIAL software. A dereplication of the ESI-MS data was realized using the feature-based molecular networking (FBMN) analysis method in the Global Natural Products Social Molecular Networking (GNPS) infrastructure, leading to 12 compound hits against the GNPS database. A total of 13 compounds were tentatively identified by means of MS data, together with the interpretation of the observed MS/MS spectra in comparison with those found in the literature. The major compounds were myricetin and quercetin glucuronides and glycosides and epichatechin-3-O-gallate. The total extract presented an antifungal effect against Candida albicans ATCC B59630 (azole-resistant) (IC50 = 2.13 µg/mL) and was not cytotoxic (IC50 > 64.00 µg/mL) in the resazurin MRC-5 SV2 cell viability assay employed. This is the first report related to chemical composition of C. cowellii plant. The research is now focused on determining the secondary metabolites responsible for the antifungal activity of the total extract. Full article

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Proceeding Paper
Synthesis of Novel Acylhydrazone-Oxazole Hybrids and Docking Studies of SARS-CoV-2 Main Protease
Chem. Proc. 2021, 3(1), 1; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08329 - 14 Nov 2020
Cited by 1 | Viewed by 333
Abstract
A novel synthetic strategy to obtain acylhydrazone-oxazole hybrids in three-step reactions in moderate to good yields is reported. The key step reaction consists in a Van Leusen reaction using a bifunctional component of both an aldehyde and a functional group. The target molecules [...] Read more.
A novel synthetic strategy to obtain acylhydrazone-oxazole hybrids in three-step reactions in moderate to good yields is reported. The key step reaction consists in a Van Leusen reaction using a bifunctional component of both an aldehyde and a functional group. The target molecules were evaluated via in-silico by molecular docking with the main protease enzyme of SARS-Cov-2, where two acyl hydralazine-oxazoles yielded good predicted free energy values in comparison to the co-crystalized ligand. Full article
Proceeding Paper
Cu.BTC MOF as a Novel and Efficient Catalyst for the Synthesis of 1,8-Dioxo-octa-hydro Xanthene
Chem. Proc. 2021, 3(1), 2; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08359 - 14 Nov 2020
Viewed by 145
Abstract
: A copper-based metal-organic framework with 1,3,5-tricarboxylic acid linkers was prepared through a facile hydrothermal method. This MOF has not been used in organic reactions widely. Cu.BTC was employed as an affordable, competent heterogeneous catalyst in 1,8-dioxo-octa-hydro xanthene synthesis. Additionally, the structure, morphology, [...] Read more.
: A copper-based metal-organic framework with 1,3,5-tricarboxylic acid linkers was prepared through a facile hydrothermal method. This MOF has not been used in organic reactions widely. Cu.BTC was employed as an affordable, competent heterogeneous catalyst in 1,8-dioxo-octa-hydro xanthene synthesis. Additionally, the structure, morphology, and porosity of this catalyst were considered. Various techniques such as FE-SEM, BET, EDS, FT-IR, and XRD applied to this aim. As a result, Cu.BTC had a mesoporous structure, an excellent specific surface area, and high purity. Some privileges of using this heterogeneous catalyst in 1,8-dioxo-octa-hydro xanthene synthesis are mild condition, increased activity, ease in separation, and reusability. Additionally, 1,8-dioxo-octa-hydro xanthene was obtained via simple recrystallization. Full article
Proceeding Paper
3-(Biphenyl)acrylates by One-Pot Suzuki Cross Coupling–Wittig Olefination Reactions
Chem. Proc. 2021, 3(1), 3; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08350 - 14 Nov 2020
Viewed by 145
Abstract
3-(Biphenyl)acrylates are prepared in good yield by one-pot Suzuki cross-coupling (Wittig olefination reactions). The central building blocks are 4-formyl- and 3-formylphenylboronic acids and the stabilized (carbomethoxymethylene)triphenylphosphorane. Examples of one-pot Suzuki–double Wittig combinations are also shown. Full article
Proceeding Paper
Synthesis of Peptidomimetics via IMCR/Post-Transformation Strategy
Chem. Proc. 2021, 3(1), 4; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08396 - 14 Nov 2020
Cited by 1 | Viewed by 151
Abstract
A series of three 2,5-Diketopiperazine (DKPs) were synthesized via one-pot process through the post- isocyanide-based multicomponent reactions (IMCR)-transformation strategy. This strategy emphasizes the role of orthogonal bifunctional reagents in the IMCR process to increase their synthetic potential, allowing us accessing a synthetic platform [...] Read more.
A series of three 2,5-Diketopiperazine (DKPs) were synthesized via one-pot process through the post- isocyanide-based multicomponent reactions (IMCR)-transformation strategy. This strategy emphasizes the role of orthogonal bifunctional reagents in the IMCR process to increase their synthetic potential, allowing us accessing a synthetic platform from which it is possible to obtain privileged heterocyclic peptidomimetics via lactamization reaction. Full article
Proceeding Paper
Crown Ether Benzoxazolyl-Alanines as Fluorimetric Chemosensors for the Detection of Palladium in Aqueous Environment
Chem. Proc. 2021, 3(1), 5; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08310 - 14 Nov 2020
Viewed by 96
Abstract
Palladium has wide application in different contexts and, as a consequence, high levels of palladium in the environment have been reported, representing a risk to human health. Considering the interest to develop more selective and sensitive chemosensors for this analyte, two novel benzoxazolyl-alanine [...] Read more.
Palladium has wide application in different contexts and, as a consequence, high levels of palladium in the environment have been reported, representing a risk to human health. Considering the interest to develop more selective and sensitive chemosensors for this analyte, two novel benzoxazolyl-alanine derivatives bearing a crown ether moiety were studied as potential fluorimetric chemosensors for palladium detection. Preliminary chemosensory studies for these unnatural amino acids in the presence of selected metal cations were performed in acetonitrile solution and in aqueous mixtures of sodium dodecyl sulfate (SDS, 20 mM, pH 7.5) solution with acetonitrile, 90:10 v/v. In acetonitrile solution, these probes had a fluorescence response for different cations but, most importantly, in SDS aqueous solution both compounds displayed a selective fluorescence response in the presence of palladium. Full article
Proceeding Paper
A New Fluorogenic Substrate for Granzyme B Based on Fluorescence Resonance Energy Transfer
Chem. Proc. 2021, 3(1), 6; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08311 - 14 Nov 2020
Viewed by 99
Abstract
The synthesis and characterization of a new fluorogenic substrate for granzyme B (GzmB) is reported. The substrate design was based on the fluorescence resonance energy transfer (FRET) principle using 5-(2′-aminoethyl)aminonaphthalene sulfonic acid (Edans) and 4-[[4′-(N,N-dimethylamino)phenyl]diazenyl]benzoic acid (Dabcyl) as a [...] Read more.
The synthesis and characterization of a new fluorogenic substrate for granzyme B (GzmB) is reported. The substrate design was based on the fluorescence resonance energy transfer (FRET) principle using 5-(2′-aminoethyl)aminonaphthalene sulfonic acid (Edans) and 4-[[4′-(N,N-dimethylamino)phenyl]diazenyl]benzoic acid (Dabcyl) as a donor–acceptor pair, linked to a specific sequence for GzmB (AAD), with an additional amino acid as the anchoring point (K). The tetrapeptide was synthesized by microwave-assisted solid-phase peptide synthesis (MW-SPPS) and coupled to Dabcyl and Edans at its N- and C-termini, respectively. The obtained probe was purified by semi-preparative HPLC and characterized by NMR, UV/Vis absorption and fluorescence spectroscopy and mass spectrometry. Full article
Proceeding Paper
A First Attempt to Identify Repurposable Drugs for Type 2 Diabetes: 3D-Similarity Search and Molecular Docking
Chem. Proc. 2021, 3(1), 7; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08368 - 14 Nov 2020
Viewed by 195
Abstract
Drug repositioning involves the investigation of existing drugs for new therapeutic purposes, such as type 2 diabetes. This disease affects the health and quality of life for individuals around the world. Sitagliptin, a highly selective dipeptidyl peptidase-4 (DPP-4) inhibitor, is used to treat [...] Read more.
Drug repositioning involves the investigation of existing drugs for new therapeutic purposes, such as type 2 diabetes. This disease affects the health and quality of life for individuals around the world. Sitagliptin, a highly selective dipeptidyl peptidase-4 (DPP-4) inhibitor, is used to treat type 2 diabetes mellitus by effective fasting and improved glycemic control. Despite this advantage, serious hypersensitivity reactions have been acknowledged for patients receiving sitagliptin. In this context, it is necessary to develop new drugs with enhanced profiles and targeting DPP-4. Sitagliptin, ((2R)-4-oxo-4-[3-(trifluoromethyl)-5,6-dihidro[1,2,4]triazolo[4,3-A]pirazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-amine), was used as a query in a 3D-similarity search on the approved DrugBank. Based on the TanimotoCombo parameter, the first 10 approved DrugBank drugs were docked in the 4FFW active site to identify effective antidiabetic effects for possible repurposable drugs marketed with other indications. Full article
Proceeding Paper
In Silico Studies on Acetylcholine Receptor Subunit Alpha-L1 for Proposal of Novel Insecticides against Aphis craccivora
Chem. Proc. 2021, 3(1), 8; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08366 - 14 Nov 2020
Viewed by 109
Abstract
: Aphis craccivora is an aphid which damages many species of plants and is also a vector for numerous plant viruses. Since neonicotinoids are a well-known class of effective insecticides with less toxicity against mammals and other vertebrates, a small dataset of compounds [...] Read more.
: Aphis craccivora is an aphid which damages many species of plants and is also a vector for numerous plant viruses. Since neonicotinoids are a well-known class of effective insecticides with less toxicity against mammals and other vertebrates, a small dataset of compounds retrieved from the literature based on similarity to highly active neonicotinoids was used. Thus, homology modeling was involved in the building of the 3D structure of the acetylcholine receptor subunit alpha-L1 of Aphis craccivora. The homology model was involved in virtual screening experiments using the FRED docking tool of the OpenEye software. The aforementioned dataset was used to explore the intermolecular ligand–target interaction patterns for a rational design of desired and relatively safe insecticides. Full article
Proceeding Paper
Interactions of Alkyl Gallates with SARS-CoV-2 Main Protease: A Molecular Docking Approach
Chem. Proc. 2021, 3(1), 9; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08360 - 14 Nov 2020
Viewed by 106
Abstract
Ten natural and semi-synthetic compounds (gallic acid and alkyl gallates) were investigated by in silico methods in order to evaluate their potential inhibitory activity against SAR-CoV-2 using the X-ray structure of SARS-CoV-2 main protease bound to Boceprevir at 1.45 Å (PDB ID: 6WNP). [...] Read more.
Ten natural and semi-synthetic compounds (gallic acid and alkyl gallates) were investigated by in silico methods in order to evaluate their potential inhibitory activity against SAR-CoV-2 using the X-ray structure of SARS-CoV-2 main protease bound to Boceprevir at 1.45 Å (PDB ID: 6WNP). The evaluation of drug-likeness in terms of Lipinski’s Rule of Five and docking results in terms of docking score and interactions with the amino acids residues from the active binding site of the target protein were reported. Full article
Proceeding Paper
An In Silico Approach to Enzymatic Synthesis of Fucooligosaccharides Using α-l-Fucosidase from Thermotoga maritima
Chem. Proc. 2021, 3(1), 10; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08303 - 14 Nov 2020
Viewed by 178
Abstract
Fucooligosaccharides comprise the primary group of human milk oligosaccharides. Due to their beneficial properties, a series of synthetic methods have been proposed to obtain them. Enzymatic methods show great promise, and α-l-fucosidase from Thermotoga maritima has emerged as a powerful catalyst [...] Read more.
Fucooligosaccharides comprise the primary group of human milk oligosaccharides. Due to their beneficial properties, a series of synthetic methods have been proposed to obtain them. Enzymatic methods show great promise, and α-l-fucosidase from Thermotoga maritima has emerged as a powerful catalyst for their production. Nonetheless, the enzyme’s limited substrate scope has delayed its wider application. The present work aims to compare the relative reactivity of fucose, pNP-fucose, and ethyl-fucose, while also exploring the molecular interactions of these fucosyl-donors with the enzyme through a combination DFT and docking analysis. The HOMO-LUMO band gaps range from −7.14571 to −4.24429 eV, with α/β-pNP-fucose and α-fucose being the three most reactive compounds. Moderate association energies between −6.4 to −5.5 kcal·mol−1 were found in the docking analysis, with α-pNP-fucose and both anomers of ethyl-fucose demonstrating the poorest affinity. In the case of α/β-lactose affinity to the β-fucose/enzyme complex, no significant differences were shown. We conclude that the best fucosyl-donors for transfucosylation are those that maintain an enzyme affinity and reactivity similar to pNP-fucose. Full article
Proceeding Paper
Design, Synthesis, and Photophysical Properties of BODIPY-Labeled Lupane Triterpenoids
Chem. Proc. 2021, 3(1), 11; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08102 - 13 Nov 2020
Viewed by 130
Abstract
Novel boron-dipyrromethene difluoride (4,4-difluoro-4-bora-3α,4α-diaza-s-indacene) (BODIPY)-lupane triterpenoid conjugates bearing a fluorescent marker at the C-2 position of ring A of the triterpene core were obtained via the Sonogashira reaction as a key step. The starting compounds in the cross-coupling reaction were C-2 propynyl derivatives [...] Read more.
Novel boron-dipyrromethene difluoride (4,4-difluoro-4-bora-3α,4α-diaza-s-indacene) (BODIPY)-lupane triterpenoid conjugates bearing a fluorescent marker at the C-2 position of ring A of the triterpene core were obtained via the Sonogashira reaction as a key step. The starting compounds in the cross-coupling reaction were C-2 propynyl derivatives of betulinic or betulonic acids and fluorescent dyes with an iodo-group at C-2 or meso position of BODIPY-platform. The newly elaborated coupling procedure might have applicability in the synthesis of fluorescently-labeled triterpenoid conjugates suitable for biological assays. Full article
Proceeding Paper
Evaluation of Reactivity (pKa) of Substituted Aromatic Diamines, Monomers for Polyamides Synthesis, via Nuclear Magnetic Resonance, NMR-1H
Chem. Proc. 2021, 3(1), 12; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08436 - 14 Nov 2020
Viewed by 160
Abstract
The relationship between properties of aromatic polyamides and the structure and pKa of substituted diamine monomers allows for modeling and designing the synthesis of polymers with special properties for different uses (dialysis membranes, ion exchange systems, to thermo-resistant materials and impact protection devices). [...] Read more.
The relationship between properties of aromatic polyamides and the structure and pKa of substituted diamine monomers allows for modeling and designing the synthesis of polymers with special properties for different uses (dialysis membranes, ion exchange systems, to thermo-resistant materials and impact protection devices). Nuclear Magnetic Resonance is a versatile analytical tool for such purposes. Based on the obtained equations (pKa = 13.1512 − 1.67039 × (ppm)), and chemical shift (, ppm) = −7.0593 − (37.57628 × φ) the reactivity of the monomers can be calculated and selectively modify some properties of polyamides. Aromatic diamines were synthetized according to established protocols and statistical-molecular studies were developed using Hyperchem pack-2005 and Mopac-6. Full article
Proceeding Paper
6-Amino-4-Aryl-3-Carbamoyl-5-Cyano-1,4-Dihydropyridine-2-Thiolates: Synthesis, Reactions and Docking Studies
Chem. Proc. 2021, 3(1), 13; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08394 - 14 Nov 2020
Viewed by 107
Abstract
New triethylammonium 6-amino-4-aryl-3-carbamoyl-5-cyano-1,4-dihydropyridine-2-thiolates were prepared in good yields by the ternary condensation of malononitrile, aldehydes and monothiomalonamide in the presence of Et3N. The thiolates underwent S-alkylation under mild conditions to produce new 1,4-dihydronicotinamides. Molecular docking studies were carried out in order [...] Read more.
New triethylammonium 6-amino-4-aryl-3-carbamoyl-5-cyano-1,4-dihydropyridine-2-thiolates were prepared in good yields by the ternary condensation of malononitrile, aldehydes and monothiomalonamide in the presence of Et3N. The thiolates underwent S-alkylation under mild conditions to produce new 1,4-dihydronicotinamides. Molecular docking studies were carried out in order to explore the interaction mechanism and to investigate suitable binding modes of the new compounds on the calcium channel proteins. Some of the compounds in the in silico experiments were found to be more potent as calcium channel blockers than the reference drug, Nifedipine. Full article
Proceeding Paper
New Quinoxaline-1,4-Dioxides Derived from Beirut Reaction of Benzofuroxane with Active Methylene Nitriles
Chem. Proc. 2021, 3(1), 14; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08391 - 14 Nov 2020
Viewed by 112
Abstract
Benzofuroxane reacts under Beirut reaction conditions with active methylene nitriles to give new 2-aminoquinoxaline-1,4-dioxides. The treatment of known 2-amino-3-cyanoquinoxaline-1,4-dioxide with chloroacetyl chloride afforded corresponding chloroacetamide which is useful for the preparation of various heterocycles bearing a quinoxaline-1,4-dioxide core system. Full article
Proceeding Paper
Alkynyl N-BODIPYs as Reactive Intermediates for the Development of Dyes for Biophotonics
Chem. Proc. 2021, 3(1), 15; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08374 - 14 Nov 2020
Viewed by 122
Abstract
A new approach for the rapid multi-functionalization of BODIPY dyes towards biophotonics is reported. It is based on novel N-BODIPYs, through reactive intermediates with alkynyl groups to be further derivatized by click chemistry. This approach has been exemplified by the development [...] Read more.
A new approach for the rapid multi-functionalization of BODIPY dyes towards biophotonics is reported. It is based on novel N-BODIPYs, through reactive intermediates with alkynyl groups to be further derivatized by click chemistry. This approach has been exemplified by the development of new dyes for cell bio-imaging, which have proven to successfully internalize into pancreatic cancer cells and accumulate in the mitochondria. The in vitro suitability for photodynamic therapy (PDT) was also analyzed and confirmed our compounds to be promising PDT candidates for the treatment of pancreatic cancer. Full article
Proceeding Paper
1′-Homocarbocyclic Nucleoside Analogs with an Optically Active Substituted Bicyclo[2.2.1]Heptane Scaffold
Chem. Proc. 2021, 3(1), 16; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08367 - 14 Nov 2020
Viewed by 96
Abstract
An optically active bicyclo[2.2.0]heptane fragment was introduced in the molecule of new 1′-homonucleosides on a 2- 6-chloro-amino-purine scaffold to obtain 6-substituted carbocyclicnucleozide analogs as antiviral compounds. The synthesis was realized by a Mitsunobu reaction of the base with the corresponding bicyclo[2.2.0]heptane intermediate, and [...] Read more.
An optically active bicyclo[2.2.0]heptane fragment was introduced in the molecule of new 1′-homonucleosides on a 2- 6-chloro-amino-purine scaffold to obtain 6-substituted carbocyclicnucleozide analogs as antiviral compounds. The synthesis was realized by a Mitsunobu reaction of the base with the corresponding bicyclo[2.2.0]heptane intermediate, and then the nucleoside analogs were obtained by substitution of the 6-chlorime with selected pharmaceutically accepted amines. A molecular docking study of the compounds on influenza, HSV and low active coronavirus was realized. Experimental screening of the compounds on the same viruses is being developed and soon will be finished. Full article
Proceeding Paper
Sustainable Synthesis of Polymeric Materials versus Fine Chemicals via CO2 Addition to Epoxides
Chem. Proc. 2021, 3(1), 17; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08357 - 14 Nov 2020
Cited by 1 | Viewed by 117
Abstract
The development of efficient chemical processes capable of transforming carbon dioxide (CO2) into value-added products constitutes one of the greatest challenges for the scientific community. In this context, the use of carbon dioxide as a C1 source is a relevant topic [...] Read more.
The development of efficient chemical processes capable of transforming carbon dioxide (CO2) into value-added products constitutes one of the greatest challenges for the scientific community. In this context, the use of carbon dioxide as a C1 source is a relevant topic and, over the last decade, there has been remarkable scientific and technological advances regarding the development of chemical processes for converting CO2 into added value products. We highlight the reaction of CO2 addition to epoxides, from which it is possible to selectively obtain two types of products: cyclic carbonates and polycarbonates, both with relevant applications as fine chemicals and polymeric materials, respectively. Full article
Proceeding Paper
Anionic Low Band Gap-Conjugated Polyelectrolytes as Hole-Transporting Layer in Optoelectronics Devices
Chem. Proc. 2021, 3(1), 18; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08406 - 14 Nov 2020
Viewed by 144
Abstract
In the last years, interfacial engineering has played a critical role in promoting the performance of optoelectronic devices as organic solar cells (OSC) and organic light-emitting diodes (OLEDs) since interfacial layers help to form an ohmic contact between the electrodes and the active [...] Read more.
In the last years, interfacial engineering has played a critical role in promoting the performance of optoelectronic devices as organic solar cells (OSC) and organic light-emitting diodes (OLEDs) since interfacial layers help to form an ohmic contact between the electrodes and the active layers, which is of great importance for charge collection/injection. Conjugated polyelectrolytes (CPEs), which are conjugated polymers bearing side-chain ionic functionalities such as anionic, cationic, or zwitterionic groups, have emerged as a new class of interfacial materials in thin film-based electronic devices thanks to their ability to reduce the barrier between electrode and active layer. In view of this, we designed and synthesized two novel low bandgap anionic copolymers with different anionic pendant groups and different conjugated backbones to obtain hole-transporting layer (HTL) materials as an alternative to commonly used poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate). The functional behavior of these copolymers as anode modifiers is herein preliminarily investigated in an OLED prototype. Full article
Proceeding Paper
Evaluation of Organophosphate Pesticide Residues in Food Using the Partial Least Squares Method
Chem. Proc. 2021, 3(1), 19; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08307 - 14 Nov 2020
Viewed by 103
Abstract
Organophosphorus (OP) chemicals were broadly used as insecticides and in the treatment of human diseases such as malaria mosquitoes, parasitosis, myasthenia, and glaucoma. The OP toxicity is well known. They can cause environmental and health problems and have the possibility to accumulate in [...] Read more.
Organophosphorus (OP) chemicals were broadly used as insecticides and in the treatment of human diseases such as malaria mosquitoes, parasitosis, myasthenia, and glaucoma. The OP toxicity is well known. They can cause environmental and health problems and have the possibility to accumulate in the food chain. The acceptable daily intake (ADI) can be considered as a measure of the effect of pesticide residues in food on human health. In this paper, the partial least squares (PLS) approach is used to evaluate the ADIs (expressed as pADIs) of a series of 46 structurally diverse OPs. OP structures were pre-optimized using the MMFF94s force field, and structural descriptors were calculated for the minimum energy conformers. This dataset was divided into 26 training compounds, and 20 pesticides were included in the prediction set. Several criteria to check the model robustness, overfitting, and the potential outliers in the X and Y space were employed. The PLS results indicated that new experimental toxicological data would be needed for five out of the 46 OPs, to improve their known ADI values, for qualitative and quantitative dietary long-term risk assessments. Full article
Proceeding Paper
Influence of Copper(I) Halides on the Reactivity of Aliphatic Carbodiimides
Chem. Proc. 2021, 3(1), 20; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08096 - 13 Nov 2020
Viewed by 111
Abstract
The influence of copper(I) halides CuX (X = Cl, Br, I) on the electronic structure of N,N′-diisopropylcarbodiimide (DICDI) and N,N′-dicyclohexylcarbodiimide (DCC) was investigated by means of computational DFT (density functional theory) methods. The coordination of the considered [...] Read more.
The influence of copper(I) halides CuX (X = Cl, Br, I) on the electronic structure of N,N′-diisopropylcarbodiimide (DICDI) and N,N′-dicyclohexylcarbodiimide (DCC) was investigated by means of computational DFT (density functional theory) methods. The coordination of the considered carbodiimides occurs by one of the nitrogen atoms, with the formation of linear complexes having a general formula of [CuX(carbodiimide)]. Besides varying the carbon–nitrogen bond lengths, the thermodynamically favourable interaction with Cu(I) reduces the electron density on the carbodiimides and alters the energies of the (NCN)-centred, unoccupied orbitals. A small dependence of these effects on the choice of the halide was observable. The computed Fukui functions suggested negligible interaction of Cu(I) with incoming nucleophiles, and the reactivity of carbodiimides was altered by coordination mainly because of the increased electrophilicity of the {NCN} fragments. Full article
Proceeding Paper
New Dibenzofuran Compounds Obtained by Dihydrousnic Acid Hydrogenation
Chem. Proc. 2021, 3(1), 21; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08460 - 16 Nov 2020
Viewed by 333
Abstract
It has been found that usnic acid carbonyl groups can be hydrogenated by the action of H2/Pd(C). Thus, two new dibenzofuran derivatives were synthesized. Full article
Proceeding Paper
Identification of Less Harmful Pesticides against Honey Bees: Shape-Based Similarity Analysis
Chem. Proc. 2021, 3(1), 22; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08342 - 14 Nov 2020
Viewed by 101
Abstract
The high concentration of pesticide residues existing in vegetation, crops, and various edible products and the prolonged exposure to them can harm human life and contribute to the disappearance of honey bees, and several avian and animal species. The honey bees (Apis mellifera), [...] Read more.
The high concentration of pesticide residues existing in vegetation, crops, and various edible products and the prolonged exposure to them can harm human life and contribute to the disappearance of honey bees, and several avian and animal species. The honey bees (Apis mellifera), which are efficient pollinators in addition to honey producers, are also considered important non-target test species for the terrestrial toxicity assessment of chemicals. In this context, using thiacloprid and acetamiprid as queries, we performed a 3D similarity search to select new potential products with less harmful effects against bees. For a similarity search, a small dataset of 302 compounds with pesticide activity, compiled from the literature, was used. The first 10 compounds were selected and structurally analyzed according to the TanimotoCombo metrics, and compared with each of these two queries, which is known to be effective, easily metabolized, and less toxic for bees. This approach came as a forward step in the research of pesticide ecotoxicological risk assessment for the evaluation of their potential impact on the pollinator insects and the environment. Full article
Proceeding Paper
New Reactions of 5-Amino-3-(Cyanomethyl)-1H-Pyrazole-4-Carbonitrile
Chem. Proc. 2021, 3(1), 23; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08398 - 14 Nov 2020
Viewed by 96
Abstract
5-Amino-3-(cyanomethyl)-1H-pyrazole-4-carbonitrile, prepared by reaction of malononitrile dimer with hydrazine, smoothly reacts with chloroacetyl chloride to form 2-chloro-N-(4-cyano-3-(cyanomethyl)-1H-pyrazol-5-yl)acetamide in good yield. The latter easily reacts with 3-cyanopyridine-2-thiolates to give hybrid molecules bearing nicotinonitrile and pyrazole units. Full article
Proceeding Paper
Synthesis of New Water-Soluble Bunte Salts Bearing Thieno[2,3-b]Pyridine-3-yl Substituents
Chem. Proc. 2021, 3(1), 24; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08397 - 14 Nov 2020
Viewed by 135
Abstract
Upon treatment with chloroacetyl chloride, 3-aminothieno[2,3-b]pyridines gave the corresponding chloroacetamides. The latter readily react with sodium thiosulphate to afford water soluble S-alkylthiosulphates with pharmacophoric heterocyclic units. Full article
Proceeding Paper
In Silico Study of Some Natural Flavonoids as Potential Agents against COVID-19: Preliminary Results
Chem. Proc. 2021, 3(1), 25; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08343 - 14 Nov 2020
Cited by 1 | Viewed by 174
Abstract
Flavonoids, widely distributed in fruits, vegetables, and medicinal herbs, are compounds with multiple biological benefits to human health from anti-inflammatory, antioxidant, anticancer, antibacterial to antiviral activity. Coronavirus disease 2019 (COVID-19), a serious concern in the world today, is a respiratory tract disease involving [...] Read more.
Flavonoids, widely distributed in fruits, vegetables, and medicinal herbs, are compounds with multiple biological benefits to human health from anti-inflammatory, antioxidant, anticancer, antibacterial to antiviral activity. Coronavirus disease 2019 (COVID-19), a serious concern in the world today, is a respiratory tract disease involving moderate to severe symptoms of pneumonia, with a major incidence in older people and patients having chronic diseases. This emergency health situation led us to evaluate the possible use of natural products to prevent respiratory diseases. The present study aims to report the potential of four natural flavonoids, known to have anti-inflammatory and antiviral activity, as anti-SARS-CoV-2 through their binding on the 6YNQ protein receptor. Molecular docking study with the FRED program was chosen as an appropriate tool to analyze the interaction of natural flavonoids, quercetin, luteolin, galangin, and naringenin, with the SARS-CoV-2 main protease and to rank the conformations through a scoring function to predict their binding affinity. Overall, our preliminary results indicate the potential of the titled natural flavonoids to fight the new coronavirus, COVID-19. Full article
Proceeding Paper
The Reactions of N,N′-Diphenyldithiomalonamide with Michael Acceptors
Chem. Proc. 2021, 3(1), 26; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08399 - 14 Nov 2020
Viewed by 102
Abstract
N,N′-diphenyldithiomalonamide (dithiomalondianilide) smoothly reacts with various Michael acceptors to give either stable Michael adducts or products of their further heterocyclization. The structure of the products was confirmed by 2D NMR experiments and X-ray data. The mechanisms of the reactions are discussed. Full article
Proceeding Paper
Microwave-Assisted Asinger Synthesis of Thiazolines
Chem. Proc. 2021, 3(1), 27; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08316 - 14 Nov 2020
Viewed by 122
Abstract
An array of 2,4-disubstituted thiazolines was obtained through Asinger reaction approach from the straightforward treatment of diverse aldehydes/ketones with 1-mercaptopropan-2-one, in the presence of NH3 assisted by microwave irradiation, displaying similar and sometimes higher yields, as well as shorter reaction times that [...] Read more.
An array of 2,4-disubstituted thiazolines was obtained through Asinger reaction approach from the straightforward treatment of diverse aldehydes/ketones with 1-mercaptopropan-2-one, in the presence of NH3 assisted by microwave irradiation, displaying similar and sometimes higher yields, as well as shorter reaction times that traditional Asinger reaction conditions at room and lower temperatures. Full article
Proceeding Paper
Thiomonosaccharide Derivatives from D-Mannose
Chem. Proc. 2021, 3(1), 28; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08424 - 14 Nov 2020
Viewed by 132
Abstract
Sulfur-containing monosaccharide derivatives can be highly valuable for obtaining compounds with biological activities. In this work, a synthetic route starting from D-mannose has been designed. After a convenient hydroxyl protection and anomeric carbon functionalization in a cyano group, a new carbohydrate analogue has [...] Read more.
Sulfur-containing monosaccharide derivatives can be highly valuable for obtaining compounds with biological activities. In this work, a synthetic route starting from D-mannose has been designed. After a convenient hydroxyl protection and anomeric carbon functionalization in a cyano group, a new carbohydrate analogue has been obtained with sulfur in the ring. The heteroatoms have been introduced by an SN2 mechanism, with subsequent cyclization. Structural identification has been performed by different spectroscopic techniques. Full article
Proceeding Paper
Synthesis and Photophysical Characterization of 2′-Aminochalcones
Chem. Proc. 2021, 3(1), 29; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08301 - 14 Nov 2020
Viewed by 107
Abstract
Chalcones present biological activity and are, therefore, currently studied for their therapeutic potential. They have shown antitumor, anti-inflammatory, antifungal and antibacterial properties. These compounds occur in nature as secondary metabolites of plants and are precursors of flavonoid biosynthesis. Generally, they are not luminescent, [...] Read more.
Chalcones present biological activity and are, therefore, currently studied for their therapeutic potential. They have shown antitumor, anti-inflammatory, antifungal and antibacterial properties. These compounds occur in nature as secondary metabolites of plants and are precursors of flavonoid biosynthesis. Generally, they are not luminescent, but derivatives with some particular patterns of substitution can present fair quantum yields. Excited State Intramolecular Proton Transfer (ESIPT) is a particular case of tautomerization, and some molecules can exhibit ESIPT fluorescence if their structures incorporate an intramolecular hydrogen bonding interaction between a hydrogen donor (-OH or -NH) and a hydrogen acceptor. If the dye is fluorescent, emission from both tautomers may be observed, leading to a dual emission. The chalcones with a strong push–pull character, compounds 2c, 3c and 4c, presented dual emission of keto–enol tautomerism as a consequence of ESIPT. Full article
Proceeding Paper
The Aminometylation of 4-(Alkylthio)-6-amino-2-oxo(thioxo)-1,2-dihydropyridine-3,5-dicarbonitriles
Chem. Proc. 2021, 3(1), 30; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08401 - 14 Nov 2020
Viewed by 91
Abstract
Easily available 2-(bis(alkylthio)methylene)malononitriles react with cyanoacetamide or cyanothioacetamide to give 4-(alkylthio)-6-amino-2-oxo(thioxo)-1,2-dihydropyridine-3,5-dicarbonitriles. Upon treatment with primary amines and/or HCHO, the compounds undergo heterocyclization to afford new pyrido[1,2-a][1,3,5]triazines or ring-condensed 1,3,5,7-tetrazocine derivatives. Full article
Proceeding Paper
In Silico Screening of Agonist and Antagonist Natural Compounds from Reported Essential Oils against Bursaphelenchus xylophilus
Chem. Proc. 2021, 3(1), 31; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08386 - 14 Nov 2020
Viewed by 98
Abstract
Chemical control has been the most effective and reliable containment strategy in integrated pest management of pine wilt disease (PWD), caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus. Yet, large spectrum nematicides can be dangerous to human health and the environment. Essential [...] Read more.
Chemical control has been the most effective and reliable containment strategy in integrated pest management of pine wilt disease (PWD), caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus. Yet, large spectrum nematicides can be dangerous to human health and the environment. Essential oils (EOs) are safer sustainable alternatives, being composed of highly active natural compounds. A survey of bibliographic data on the detailed chemical composition and activity of the EOs used against the PWN allowed pinpointing monoterpenes as the main source of structures with agonist or antagonist properties. Transversal EO data treatment can identify potential highly active anti-PWN compounds. Full article
Proceeding Paper
Preparation and Hydro-Lipophilic Properties of Novel Fluorinated Benzyl Carbamates of 4-Aminosalicylanilides
Chem. Proc. 2021, 3(1), 32; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08094 - 13 Nov 2020
Viewed by 89
Abstract
A series of seven fluorinated benzyl carbamates of 4-aminosalicylanilides and unsubstituted benzyl [3-hydroxy-4-(phenylcarbamoyl)phenyl]carbamate designed as agents with the expected anticholinesterase and anti-inflammatory activity were prepared and characterized. As lipophilicity significantly influences the biological activity of compounds, the hydro-lipophilic properties of these mono-, di-, [...] Read more.
A series of seven fluorinated benzyl carbamates of 4-aminosalicylanilides and unsubstituted benzyl [3-hydroxy-4-(phenylcarbamoyl)phenyl]carbamate designed as agents with the expected anticholinesterase and anti-inflammatory activity were prepared and characterized. As lipophilicity significantly influences the biological activity of compounds, the hydro-lipophilic properties of these mono-, di-, and tri-substituted carbamates were investigated in this study. All the discussed derivatives of 4-{[(benzyloxy)carbonyl]amino}-2-hydroxybenzoic acid were analyzed using reversed-phase high performance liquid chromatography to measure lipophilicity. The procedure was performed under isocratic conditions with methanol as an organic modifier in the mobile phase using an end-capped non-polar C18 stationary reversed-phase column. In the present study, the correlations between the logarithm of the capacity factor k, the logarithm of the distributive parameter D at pH 7.4, and log P/Clog P values calculated in various ways as well as the relationships between the lipophilicity and the chemical structure of the studied compounds are discussed. Full article
Proceeding Paper
Comparative Studies of Various NNRTIs in the Active Site of Different HIV-1RT Receptors
Chem. Proc. 2021, 3(1), 33; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08313 - 14 Nov 2020
Cited by 1 | Viewed by 100
Abstract
HIV is one of the most deadly viruses known to humans and causes a disease, known as Acquired Immunodeficiency Syndrome (or, AIDS). There are only a handful of drugs which are totally effective against the virus. This is due to the enzyme reverse [...] Read more.
HIV is one of the most deadly viruses known to humans and causes a disease, known as Acquired Immunodeficiency Syndrome (or, AIDS). There are only a handful of drugs which are totally effective against the virus. This is due to the enzyme reverse transcriptase present within the virus. Due to various mutations in the enzyme, the virus becomes unresponsive towards the drugs. In the present study, docking studies of the standard non-nucleoside reverse transcriptase inhibitors were performed in the non-nucleoside inhibitory binding pocket of reverse transcriptase enzymes of wild type and the resistant strains of HIV-1RT virus with PDB IDs 1RT2, 1KLM, 3BGR, and 1JLB, respectively, by using Autodock version 4.5.6. A comparison of different compounds docked into the active site of various HIV-1RT strains was carried out. The obtained results indicate that most of the compounds docked into the active site of the different receptors, such as 1RT2, 1KLM, 3BGR, and 1JLB, with good docking scores, are comparable to that of the internal standard (TNK 651) of the wild type strain of HIV-1 virus. A comparison was made based on the binding modes of the compounds in the active site of all the four receptors. Full article
Proceeding Paper
On the Acylation of 1,6-Diamino-2-oxo-1,2-dihydropyridine-3,5-dicarbonitriles
Chem. Proc. 2021, 3(1), 34; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08315 - 14 Nov 2020
Viewed by 83
Abstract
Here, 1,6-diamino-2-oxo-1,2-dihydropyridine-3,5-dicarbonitriles, prepared by the reaction of cyanoacethydrazide with arylmethylene malononitriles, react with 1-cyanoacetyl-3,5-dimethylpyrazole and chloroacetyl chloride to give corresponding cyanoacetamides and chloroacetamides. The reaction with phthalic anhydride proceeds under harsh conditions to give 4,7-dioxo-4,7-dihydropyrido[1′,2′:2,3][1,2,4]triazolo[5,1-a]isoindole- 1,3-dicarbonitriles. Full article
Proceeding Paper
Stable Anionic σ-Complexes of Highly Electrophilic Aromatics and C-Nucleophiles: Synthesis and Oxidation
Chem. Proc. 2021, 3(1), 35; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08437 - 15 Nov 2020
Viewed by 327
Abstract
Reactions of dinitrobenzoannulated heterocycles (furazan, thiadiazole, selenadiazole, pyridine) with anionic C-nucleophiles (mono- and diketones, nitroalkanes and related compounds) provided stable anionic adducts in high yields. Consecutive oxidation with ammonium cerium (IV) nitrate resulted in re-aromatization with the formation of the corresponding substitution products, [...] Read more.
Reactions of dinitrobenzoannulated heterocycles (furazan, thiadiazole, selenadiazole, pyridine) with anionic C-nucleophiles (mono- and diketones, nitroalkanes and related compounds) provided stable anionic adducts in high yields. Consecutive oxidation with ammonium cerium (IV) nitrate resulted in re-aromatization with the formation of the corresponding substitution products, formally representing C-H-functionalized benzoheterocycles. Full article
Proceeding Paper
Synthesis and Insecticidal Activity of O-alkylated Oxirane Eugenol Derivatives
Chem. Proc. 2021, 3(1), 36; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08335 - 14 Nov 2020
Viewed by 155
Abstract
The synthesis of three O-alkylated eugenol derivatives, bearing a hydroxypropyl chain and propyl esters, were synthesized and further converted into the corresponding oxiranes. Oxirane derivatives were then evaluated against their effect upon the viability of the insect cell line Sf9 (Spodoptera [...] Read more.
The synthesis of three O-alkylated eugenol derivatives, bearing a hydroxypropyl chain and propyl esters, were synthesized and further converted into the corresponding oxiranes. Oxirane derivatives were then evaluated against their effect upon the viability of the insect cell line Sf9 (Spodoptera frugiperda), in comparison with the starting O-alkylates. The results pointing to their potential as bioinsecticides, with structural changes eliciting significant effects in terms of potency. Full article
Proceeding Paper
Carvacrol Derivatives with Potential Insecticidal Activity
Chem. Proc. 2021, 3(1), 37; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08334 - 14 Nov 2020
Viewed by 136
Abstract
Three new carvacrol derivatives 13 possessing aliphatic carbon chains with different sizes as hydroxyl group substituents were synthesized in order to evaluate their insecticidal activity against the insect cell line Sf9 (Spodoptera frugiperda). Full article
Proceeding Paper
A Study about the Use of Co or Mn-Based Nanocatalysts for Styrene Epoxidation Reaction
Chem. Proc. 2021, 3(1), 38; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08312 - 14 Nov 2020
Viewed by 103
Abstract
A new catalytic system consisting of Mn or Co nanoparticles supported on different materials (celite, zeolite, activated carbon, CeO2, ZnO, MgO, Nb2O5) have been studied for styrene epoxidation. The catalysts were easily prepared from commercially available starting [...] Read more.
A new catalytic system consisting of Mn or Co nanoparticles supported on different materials (celite, zeolite, activated carbon, CeO2, ZnO, MgO, Nb2O5) have been studied for styrene epoxidation. The catalysts were easily prepared from commercially available starting materials. Reaction conditions were optimized by testing different solvents, reaction temperatures, oxidizing agents, and optimal catalyst loading. CoNPs/MgO and TBHP as a co-oxidant, in refluxing ACN, allowed total conversion to the epoxide with excellent yield and high selectivity. Full article
Proceeding Paper
Nanosystems for the Encapsulation and Release of Plant Extracts with Insecticidal Activity
Chem. Proc. 2021, 3(1), 39; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08332 - 14 Nov 2020
Viewed by 163
Abstract
Encapsulation in suitable nanostructures is a relevant strategy for the preservation and controlled release of bioactive compounds, allowing a safe application. In this work, dichloromethane extracts of Mentha suaveolens Ehrh. and Phytolacca americana L. were encapsulated in chitosan nanostructures and liposomes of soybean [...] Read more.
Encapsulation in suitable nanostructures is a relevant strategy for the preservation and controlled release of bioactive compounds, allowing a safe application. In this work, dichloromethane extracts of Mentha suaveolens Ehrh. and Phytolacca americana L. were encapsulated in chitosan nanostructures and liposomes of soybean lecithin, considering their potential as biopesticides. Liposomes were prepared either by thin film hydration or ethanolic injection methods. For chitosan, the ionic gelation technique was used. The nanosystems were characterized regarding their size and polydispersity. Encapsulation efficiencies of the extracts were determined (being higher than 60%) and the release profiles were measured. Liposomes generally allowed a delayed release of the extracts, while chitosan nanosystems were suitable for a faster and complete release of the potential bioinsecticides. Full article
Proceeding Paper
Fluorescent Calix[4]arene-Oxacyclophane Sensor for Transition Metal Cations
Chem. Proc. 2021, 3(1), 40; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08453 - 16 Nov 2020
Viewed by 362
Abstract
The sensing behavior of a calix[4]arene-oxacyclophane-carbazole conjugate (1) towards Cu(I) ions was investigated. Contrary to the noteworthy sensitivity and selectivity previously found for Cu(II), the affinity of 1 for Cu(I) cations is much lower. Through fluorescence titration assays, the apparent binding [...] Read more.
The sensing behavior of a calix[4]arene-oxacyclophane-carbazole conjugate (1) towards Cu(I) ions was investigated. Contrary to the noteworthy sensitivity and selectivity previously found for Cu(II), the affinity of 1 for Cu(I) cations is much lower. Through fluorescence titration assays, the apparent binding constants (Ka) for the two ions were determined, showing that an affinity of over thirteen fold was displayed for Cu(II). Two Cu(I) counter-ions were used to determine possible effects on the binding event. It was found that acetate and iodide ions behave similarly, yielding Ka of the same magnitude. Formation of a ground-state supramolecular complex between 1 and Cu(I) ions was not observed on UV-Vis titrations, in contrast to what was previously reported for Cu(II) using the same host. The affinity of 1 for Fe(III), a major biological competitor, was also assessed. The fluorescence of host 1 is quenched by Fe(III) ions although to a lesser extent (32% less efficient than Cu(II)). The study demonstrates that calixarene 1 is able to differentiate copper ions in two common oxidation states using fluorescence techniques, thereby suggesting its application for redox-active centers in biomimetic chemistry. Full article
Proceeding Paper
Synthesis and Preliminary Antibacterial Evaluation of A 2,4,5-Tri(hetero)arylimidazole Derivative
Chem. Proc. 2021, 3(1), 41; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08331 - 14 Nov 2020
Viewed by 109
Abstract
The imidazole ring is a planar heterocycle whose derivatives are applied in several scientific areas, such as medicinal, materials and supramolecular chemistry. The presence of the imidazole ring in these structures is the key to the development of new drugs, since it is [...] Read more.
The imidazole ring is a planar heterocycle whose derivatives are applied in several scientific areas, such as medicinal, materials and supramolecular chemistry. The presence of the imidazole ring in these structures is the key to the development of new drugs, since it is ubiquitous in naturally occurring biological structures. Therefore, over the past few decades, several imidazole derivatives have been synthesized and occupy a unique position in the field of medicinal chemistry due to their diverse biological activities. In order to continue the work developed by the research group, we report the synthesis of 2,4,5-tri(hetero)arylimidazole derivatives and their characterization by 1H and 13C nuclear magnetic resonance (NMR) and UV-Vis absorption spectroscopies. As a complement to the characterization of the synthesized 2,4,5-tri(hetero)arylimidazole derivatives, a screening for antibacterial activity showed the inhibition of Staphylococcus aureus proliferation, suggesting antibacterial activity. Therefore, these new compounds have the potential for the development of new drugs. Full article
Proceeding Paper
Stokesia laevis Ethanolic Extract Activity on the Normal and Malignant Murine Cell Line Viability L969 and B16
Chem. Proc. 2021, 3(1), 42; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08318 - 14 Nov 2020
Viewed by 104
Abstract
: Stokesia laevis (common name Stokes aster) ethanolic extract (Slae26) containing 5 mg GAE/mL extract was investigated to establish cytotoxicity and anti-proliferative effects. The assays were performed on normal murine fibroblast cell line L929 and malignant murine melanoma cell line B16, respectively; for [...] Read more.
: Stokesia laevis (common name Stokes aster) ethanolic extract (Slae26) containing 5 mg GAE/mL extract was investigated to establish cytotoxicity and anti-proliferative effects. The assays were performed on normal murine fibroblast cell line L929 and malignant murine melanoma cell line B16, respectively; for the first time in literature data, potential cytotoxic and anti-proliferative effects of the ethanolic extract from S. laevis on both, normal murine fibroblast cell line L929, and murine melanoma cell line B16 have been proved. The study is supplemented by molecular docking simulations of the major components of Slae26 against human tyrosinase receptor, to evaluate possible melanogenesis inhibition. Full article
Proceeding Paper
Synthesis of Myrtenal through Allylic Oxidation of α-Pinene over a Pd/SeO2/SiO2 Catalyst
Chem. Proc. 2021, 3(1), 43; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08382 - 14 Nov 2020
Viewed by 176
Abstract
SeO2 based samples are tested for the oxidation of α-pinene, in liquid phase employing ethanol as the solvent. Commercial SeO2 was tested under both reflux and under 6 atm O2 pressure. At conversion levels of approximately 40%, the yield to [...] Read more.
SeO2 based samples are tested for the oxidation of α-pinene, in liquid phase employing ethanol as the solvent. Commercial SeO2 was tested under both reflux and under 6 atm O2 pressure. At conversion levels of approximately 40%, the yield to myrtenal was much higher in the latter (34.4%) than in the former case (18.0%) due to the high oxidant species availability. Besides the high yield attained at relatively short reaction time. A palladium promoted selenium dioxide supported catalyst (Pd/SeO2/SiO2) was prepared, characterized, and submitted to the catalytic test. Selenium dioxide (14.4%) was strongly fixed to the silica support. Upon the palladium introduction (0.98%), the reducibility of SeO2 is modified, which originates a selenium species activation towards the allylic oxidation. A 12% conversion level is attained over Pd/SeO2/SiO2 following 8 h of reaction time, employing ethanol as the solvent at 134 °C. The main product is myrtenal, being obtained with a selectivity of 62%. Over oxidation products are not detected. The palladium/selenium dioxide sample is easy to handle with and its recuperation following the reaction in liquid phase is possible. Full article
Proceeding Paper
Synthesis of Tetrakis-Tetrazole via a Repetitive MCR
Chem. Proc. 2021, 3(1), 44; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08395 - 14 Nov 2020
Viewed by 105
Abstract
The synthesis of novel and complex molecules of tetrakis-tetrazole was done via a Ugi-azide repetitive reaction from easily accessible starting materials in good yields. The use of orthogonal bifunctional reagents in isocyanide-based multicomponent reactions (IMCR) allowed the synthesis of structurally complex molecules in [...] Read more.
The synthesis of novel and complex molecules of tetrakis-tetrazole was done via a Ugi-azide repetitive reaction from easily accessible starting materials in good yields. The use of orthogonal bifunctional reagents in isocyanide-based multicomponent reactions (IMCR) allowed the synthesis of structurally complex molecules in one pot manner. The molecules herein synthesized could have applications such as use as chelating agents and organocatalysts. Full article
Proceeding Paper
Glucose-Based Molecular Rotors as Fluorescent Inhibitors and Probes of Glycogen Phosphorylase
Chem. Proc. 2021, 3(1), 45; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08414 - 14 Nov 2020
Viewed by 114
Abstract
In this study, (E)-2-cyano-3-(6-(dimethylamino)naphthalen-2-yl)-N-(β-d-glucopyranosyl)acrylamide, a β-d-glucopyranosyl analogue of the widely used molecular rotor julolidine, was synthesized and studied photochemically. The new compound is a fluorescent inhibitor of rabbit muscle glycogen phosphorylase with properties of a molecular rotor. Fluorescence measurements [...] Read more.
In this study, (E)-2-cyano-3-(6-(dimethylamino)naphthalen-2-yl)-N-(β-d-glucopyranosyl)acrylamide, a β-d-glucopyranosyl analogue of the widely used molecular rotor julolidine, was synthesized and studied photochemically. The new compound is a fluorescent inhibitor of rabbit muscle glycogen phosphorylase with properties of a molecular rotor. Fluorescence measurements in solutions of increasing viscosity determined that the fluorescence intensity increases with the viscosity of the medium, indicating that the new compound exhibits molecular rotor characteristics. Although the compound fluoresces negligibly in an aqueous buffer solution, in the presence of increasing amounts of rabbit muscle glycogen phosphorylase, we observed an increase in fluorescence intensity, which was attributed to the formation of an inhibitor–enzyme complex. In-vitro cellular studies were also undertaken, yielding promising preliminary results for the use of the new compound as a fluorescent probe. Full article
Proceeding Paper
Molecular Docking Studies on Synthetic Therapeutic Agents for COVID-19
Chem. Proc. 2021, 3(1), 46; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08352 - 14 Nov 2020
Viewed by 141
Abstract
Coronavirus disease (COVID-19) is an infectious disease caused by coronavirus 2 (SARS-CoV-2) which was detected for the first time in Wuhan China in December 2019. The rapid spread of this highly contagious and pathogenic virus led to the declaration of the pandemic by [...] Read more.
Coronavirus disease (COVID-19) is an infectious disease caused by coronavirus 2 (SARS-CoV-2) which was detected for the first time in Wuhan China in December 2019. The rapid spread of this highly contagious and pathogenic virus led to the declaration of the pandemic by the World Health Organization (WHO) on March 11, 2020. In these conditions, the discovery of new antiviral agents is extremely important. For the development of the anti-SARS-CoV-2 drugs, the fastest way is to find potential molecules from the marketed drugs by molecular docking studies. Full article
Proceeding Paper
Theoretical Study of the Aza˗Wittig Reaction, Me3P=NR (R = Methyl or Phenyl) with Aldehyde Using the DFT and DFT-D Methods (Dispersion Correction)
Chem. Proc. 2021, 3(1), 47; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08349 - 14 Nov 2020
Viewed by 85
Abstract
: The Aza-Wittig reaction plays an important role in organic transformations and has seen considerable development in the construction of cyclic and acyclic compounds in neutral solvents in the absence of catalysts with a high yield of products. Today, the use of iminophosphoranes [...] Read more.
: The Aza-Wittig reaction plays an important role in organic transformations and has seen considerable development in the construction of cyclic and acyclic compounds in neutral solvents in the absence of catalysts with a high yield of products. Today, the use of iminophosphoranes (phosphazenes) has become a powerful tool in organic synthesis strategies directed toward the construction of nitrogenous heterocycles. These can react with carbonyl compounds, an excellent method for the construction of C=N double bonds via intermolecular and intramolecular Aza-Wittig reactions. In this study, we are interested in the theoretical study of the reaction path of the Aza˗Wittig reaction between trimethyl-iminophosphoranes (CH3)3P=NR, R = CH3 or Ph) for the two-substituent methyl and phenyl with acetaldehyde, including continuum solvation. Our calculations were carried out by means of ab initio calculations using DFT (Density Function Theory) with a dispersion correction term using the Grimme method in the program Gaussian09, using the functional B3LYP-GD3BJ with a 6-31G** base. The results obtained allowed us to highlight the mechanisms of the Aza-Wittig reaction in particular after the addition of the term of dispersion correction or van der Waals correction, which provides a new description of this reaction and its chemical path. Full article
Proceeding Paper
Towards Greener Mechanosynthesis of Functional Calixarenes
Chem. Proc. 2021, 3(1), 48; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08405 - 14 Nov 2020
Viewed by 126
Abstract
The awareness of sustainability led to increasing global demand for processes that use lower energy, produce reduced waste, use fewer organic solvents, and offer improved selectivity. In this context, mechanochemistry re-emerged as a powerful green methodology. The conventional synthesis and functionalization of calixarenes, [...] Read more.
The awareness of sustainability led to increasing global demand for processes that use lower energy, produce reduced waste, use fewer organic solvents, and offer improved selectivity. In this context, mechanochemistry re-emerged as a powerful green methodology. The conventional synthesis and functionalization of calixarenes, both on the upper and lower rim, has been the subject of numerous studies but only a few were reported using a mechanochemical approach. Herein, we present new mechanically assisted key synthetic steps towards a more sustainable route to calix[4]arenes functionalized in the lower rim. Full article
Proceeding Paper
In Silico Study of the Interaction between Casein with Tocopherols: Preliminary Evaluation of Lipophilic Substrate Inclusion on Proteic Matrix
Chem. Proc. 2021, 3(1), 49; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08345 - 14 Nov 2020
Viewed by 181
Abstract
Bovine casein is a family of milk proteins with hydrophilic and hydrophobic regions that show block distribution within the protein chain. These amphiphilic properties offer great potential as a material for use as a matrix for transporting active materials such as tocopherol. In [...] Read more.
Bovine casein is a family of milk proteins with hydrophilic and hydrophobic regions that show block distribution within the protein chain. These amphiphilic properties offer great potential as a material for use as a matrix for transporting active materials such as tocopherol. In this work, we aimed to evaluate the interaction of α1-casein, the main fraction of casein, with vitamin E by docking calculations. Docking studies were conducted using SwissDock and DockThor servers. Using specific scoring functions based on energy terms, the best protein–ligand binding models were obtained. The observed interactions between vitamin E and amino acid residues consisted of several hydrophobic interactions (e.g., with Tyr119, Ala144, Trp179, Met211, Pro212). A few hydrogen bonds were observed between the phenyl group of vitamin E and the carboxylate group of the glutamic acid residue (e.g., with Glu85, Glu148). In conclusion, the results suggest that there is a major interaction of vitamin E with random coil structure and interaction with segments formed by α-helix and β-sheet. This implies that in random coil segments there is a predominance of hydrophobic domains. Full article
Proceeding Paper
A New Approach to 7-Amino-4-oxo-4,5-dihydro-3H-pyrano[2,3-d]pyrimidine-6-carbonitriles
Chem. Proc. 2021, 3(1), 50; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08105 - 13 Nov 2020
Viewed by 80
Abstract
S-alkyl derivatives of thiobarbituric acid easily react with arylmethylene malononitriles in the presence of base to give new 7-amino-4-oxo-4,5-dihydro-3H-pyrano[2,3-d]pyrimidine-6-carbonitriles. The structure of products and the mechanism of formation are discussed. Full article
Proceeding Paper
Preparation of Cu4SnS4/CuCo2S4 Nanoparticles Using Combustion Reaction Accelerated by Organic Driving Agents under Microwave Irradiation
Chem. Proc. 2021, 3(1), 51; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08354 - 14 Nov 2020
Viewed by 86
Abstract
Copper-based sulfide-rich nanomaterials have recently attracted attention in various applications due to the lack of expense, abundance, and non-toxicity of their constituent elements. As the members of this family, Cu4SnS4 and CuCo2S4 have exhibited good capability in [...] Read more.
Copper-based sulfide-rich nanomaterials have recently attracted attention in various applications due to the lack of expense, abundance, and non-toxicity of their constituent elements. As the members of this family, Cu4SnS4 and CuCo2S4 have exhibited good capability in a stable manner in solar cells, energy storage electrodes, batteries, etc. In this work, through a facile and rapid combustion reaction accelerated by microwave irradiation, Cu4SnS4/CuCo2S4 nanoparticles were prepared. Thiourea was used as a sulphur source and also organic driving agent. The features of the synthesized product were studied using FT-IR, XRD, SEM, and EDX techniques. The FT-IR and XRD results showed the formation of a multi-components structure containing orthorhombic crystalline phase of Cu4SnS4 alongside carrollite CuCo2S4 phase. Full article
Proceeding Paper
Microwave Assisted Synthesis of CoFe2O4 Nanoparticles by Utilizing Organic Promoters and Evaluation of Its Properties
Chem. Proc. 2021, 3(1), 52; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08351 - 14 Nov 2020
Viewed by 110
Abstract
Nano-sized spinel ferrites are highly regarded owing to their special optical, electrical, and magnetic properties. Cobalt ferrite (CoFe2O4) is a nominee of particular interest due to its high saturation magnetization, high coercivity, strong anisotropy, and excellent chemical stability. The [...] Read more.
Nano-sized spinel ferrites are highly regarded owing to their special optical, electrical, and magnetic properties. Cobalt ferrite (CoFe2O4) is a nominee of particular interest due to its high saturation magnetization, high coercivity, strong anisotropy, and excellent chemical stability. The synthesis of these materials with a pure crystalline phase is sometimes limited due to the required high temperatures for their calcination. In this work, we report a one-pot simple synthesis procedure of cobalt ferrite by the auto-combustion under microwave irradiation into a domestic microwave oven with a power of 900 W for 30 min. Glycine and ammonium nitrate were used as organic promoters and metal nitrates as precursors. The synthesized nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersion of X-ray spectrometry (EDX) techniques. The electrochemical properties and capability of the prepared product as a pseudocapacitive material were evaluated using cyclic voltammetry (CV) tests in details. Full article
Proceeding Paper
s-Triazine: A Multidisciplinary and International Journey
Chem. Proc. 2021, 3(1), 53; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08502 - 20 Nov 2020
Viewed by 330
Abstract
2,4,6-Trichloro-1,3,5-triazine (TCT) offers the unique ability to undergo sequential nucleophilic substitution reactions using regular nucleophiles (first Cl replacement at 0 °C, second at RT, and third at >90 °C), making s-triazine a privileged scaffold-finding application in drug development with an extension towards the [...] Read more.
2,4,6-Trichloro-1,3,5-triazine (TCT) offers the unique ability to undergo sequential nucleophilic substitution reactions using regular nucleophiles (first Cl replacement at 0 °C, second at RT, and third at >90 °C), making s-triazine a privileged scaffold-finding application in drug development with an extension towards the development of new materials. This selective chemical property of TCT fulfills the goal of chemists to control organic structures and make them react in the required conditions for achieving each objective. In this regard, orthogonality and chemoselectivity are two modern organic chemistry concepts which have been exploited in various areas of research, ranging from supramolecular chemistry to organic/bioconjugation chemistry. We have demonstrated the fusion of these two concepts using TCT as “Orthogonal Chemoselectivity” and defined it as discrimination between reactive sites in any order. The usage of azide as one of the nucleophiles modulated the reactivity of the s-triazine core for the last Cl replacement. This allowed us to overcome the barrier of higher temperature (>90 °C) for the last Cl replacement which happened at RT, taking advantage of side chains of Cys, Tyr and Lys in a biological context. In this presentation, we revise the chemistry developed in our laboratories to manipulate the TCT core for application in our medicinal chemistry programs and in bioconjugation. Full article
Proceeding Paper
Synthesis of 1,2,3-Triazoles from Alkyne-Azide Cycloaddition Catalyzed by a Bio-Reduced Alkynylcopper (I) Complex
Chem. Proc. 2021, 3(1), 54; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08384 - 14 Nov 2020
Viewed by 107
Abstract
A small library of 1,2,3-triazoles was synthesized from diverse alkynes and azides using catalytic amounts of an alkynylcopper (I) complex, which in turn was prepared from direct treatment of phenylacetylene with a Fehling reagent in the presence of glucose as a reducing agent. [...] Read more.
A small library of 1,2,3-triazoles was synthesized from diverse alkynes and azides using catalytic amounts of an alkynylcopper (I) complex, which in turn was prepared from direct treatment of phenylacetylene with a Fehling reagent in the presence of glucose as a reducing agent. The results suggest that copper-catalyzed azide alkyne cycloaddition (CuAAC) reactions require only 0.5 mg/mmol copper (I) phenylacetylide without any further additives. Full article
Proceeding Paper
Synthesis and Leishmanicidal Activity of Molecular Hybrids 1,2,3-Triazole-Chalcones
Chem. Proc. 2021, 3(1), 55; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08356 - 14 Nov 2020
Cited by 1 | Viewed by 441
Abstract
Leishmaniasis is a largely neglected infection caused by Leishmania spp. parasites. The first-line treatment, antimoniate meglumine, has a large number of adverse effects, high cost and is prone to resistance development, hence the necessity of new alternatives. We report the synthesis of (2E)-1-[1-(4-methoxyphenyl)-5-methyl-1H-1,2,3-triazol-4-yl]-3-arylprop-2-en-1-one [...] Read more.
Leishmaniasis is a largely neglected infection caused by Leishmania spp. parasites. The first-line treatment, antimoniate meglumine, has a large number of adverse effects, high cost and is prone to resistance development, hence the necessity of new alternatives. We report the synthesis of (2E)-1-[1-(4-methoxyphenyl)-5-methyl-1H-1,2,3-triazol-4-yl]-3-arylprop-2-en-1-one derivatives and the in vitro evaluation of their leishmanicidal activities. A series of 16 compounds were synthesized in three steps starting from p-anisidine with moderate to good yields and their biological activities were evaluated in vitro against Leishmania mexicana promastigotes and RAW 264.7 cells. The synthesis of 1,2,3-triazol and chalcone moieties were made using a cycloaddition with acetylacetone followed by a Claisen-Schmidt condensation using different substituted benzaldehydes. Nine compounds were active against L. mexicana with IC50 between 1.0 and 29.2 µM. Full article
Proceeding Paper
Density Functional Theory (DFT) and Thermodynamics Calculations of Amino Acids with Polar Uncharged Side Chains
Chem. Proc. 2021, 3(1), 56; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08420 - 14 Nov 2020
Viewed by 173
Abstract
The goal of the present work was to evaluate the chemical reactivity of amino acids with polar uncharged side chains (serine, threonine, asparagine and glutamine) using density functional theory (DFT) and thermodynamics modeling by calculating a series of molecular descriptors and properties of [...] Read more.
The goal of the present work was to evaluate the chemical reactivity of amino acids with polar uncharged side chains (serine, threonine, asparagine and glutamine) using density functional theory (DFT) and thermodynamics modeling by calculating a series of molecular descriptors and properties of their optimized geometries. The predictive calculations were achieved with Spartan software from Wavefunction, Inc. Irvine, CA, USA, hybrid algorithm B3LYP (Becke’s three-term functional; Lee, Yang, Parr exchange hybrid) and polarization basis set 6-31G(d,p) for equilibrium geometry at ground state in vacuum and in water, after energy minimization and geometry optimization. Thermodynamic properties (zero-point energy, enthalpy, constant volume heat capacity, entropy and Gibbs energy) for these derivatives were calculated and related to electrochemical ligand behavior. Reduction and oxidation potentials were correlated to their calculated energy levels for molecular orbitals. Full article
Proceeding Paper
Cycloaddition of Thiourea- and Guanidine-Substituted Furans to Dienophiles: A Comparison of the Environmentally-Friendly Methods
Chem. Proc. 2021, 3(1), 57; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08380 - 14 Nov 2020
Viewed by 98
Abstract
The cycloaddition strategy was employed in order to obtain a 7-oxanorbornene framework substituted with a guanidine moiety or its precursor functional groups: protected amine or thiourea. In order to optimize the conditions for the cycloaddition, several environmentally-friendly methods—microwave assisted organic synthesis, high pressure [...] Read more.
The cycloaddition strategy was employed in order to obtain a 7-oxanorbornene framework substituted with a guanidine moiety or its precursor functional groups: protected amine or thiourea. In order to optimize the conditions for the cycloaddition, several environmentally-friendly methods—microwave assisted organic synthesis, high pressure synthesis, high speed vibrational milling, and ultrasound assisted synthesis—were employed. The outcomes of the cycloaddition reactions were interpreted in terms of endo/exo selectivity, the conversion of the reactants to the product, and the isolated yields. In general, our results indicated the HP and HSVM approaches as the methods of choice to give good yields and conversions. Full article
Proceeding Paper
Study of Organic Radicals Generated upon Naphthoquinone-Hydantoins Reactions in Basic Aqueous Solution
Chem. Proc. 2021, 3(1), 58; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08415 - 14 Nov 2020
Viewed by 110
Abstract
In this work, the synthesis of thiohydantoins from l-amino acids and isothiocyanates was studied, using a high purity method based on the Edman cycle. This process, expected to occur through the Michael addition to a series of 1,4-naphthoquinone derivatives did not lead to [...] Read more.
In this work, the synthesis of thiohydantoins from l-amino acids and isothiocyanates was studied, using a high purity method based on the Edman cycle. This process, expected to occur through the Michael addition to a series of 1,4-naphthoquinone derivatives did not lead to the expected final product, rather leading to a colored mixture of compounds, where EPR spectra showed that some of them presented unpaired electrons, indicating that an electron transfer pathway was also involved in the reaction mixture. Detected organic radicals proved to be stable albeit with the use of different experimental conditions. Voltammetric results indicated that the reactions led to the formation of electroactive species, probably derived by homogeneous electron transfer between the reactive quinone moieties and the oxidizable urea functions within the hydantoin species. Full article
Proceeding Paper
A One-Pot Synthesis of Fluoro α-Acylamino Amide-Xanthates via an IMCR-Post Transformation Strategy
Chem. Proc. 2021, 3(1), 59; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08421 - 14 Nov 2020
Viewed by 105
Abstract
A series of six novel amide-xanthate products containing several fluorine atoms were prepared in moderate to good yields (40–92%) via an isocyanide-based multicomponent reaction (IMCR) of 5-CR by Ugi-4CR followed by an SN2 sequence in a one-pot manner. The design of [...] Read more.
A series of six novel amide-xanthate products containing several fluorine atoms were prepared in moderate to good yields (40–92%) via an isocyanide-based multicomponent reaction (IMCR) of 5-CR by Ugi-4CR followed by an SN2 sequence in a one-pot manner. The design of molecules with fluorine atoms is of interest in medicinal chemistry and a research line of our interest. The role of fluorine atoms in biological properties is well documented, improving bioavailability, lipophilicity, and metabolic resistance in bioactive molecules. Full article
Proceeding Paper
Facile Microwave-Assisted Preparation of Hetero-Structured CuCo2S4/CuCo2O4 Nanoparticles Using Organic Agent of Thiourea
Chem. Proc. 2021, 3(1), 60; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08347 - 14 Nov 2020
Viewed by 85
Abstract
Ultra-fast one-put microwave assisted strategy was introduced for the synthesis of hetero-structured CuCo2S4/CuCo2O4 nanoparticles into a domestic microwave oven with the power of 900 W for 20 min. Thiourea as an organic agent was used as [...] Read more.
Ultra-fast one-put microwave assisted strategy was introduced for the synthesis of hetero-structured CuCo2S4/CuCo2O4 nanoparticles into a domestic microwave oven with the power of 900 W for 20 min. Thiourea as an organic agent was used as a sulfur source and driving agent to lead the solvent free combustion reaction to obtain this earth-abundant and low-cost mixed chalcogenide/oxide product. The structural and morphological specifications were studied in details using powder x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT−IR), scanning electron microscopy (SEM), and energy dispersion of x-ray spectrometry (EDX). The employed strategy relatively clarifies a new facile, rapid, and eco-friendly route to produce heterostructured nanocomposites for different functional purposes. Full article
Proceeding Paper
Synthesis of Triphenylamine-Imidazo[1,2-a]pyridine via Groebke–Blackburn–Bienaymé Reaction
Chem. Proc. 2021, 3(1), 61; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08422 - 14 Nov 2020
Viewed by 101
Abstract
A series of triphenylamine-imidazo[1,2-a]pyridine were synthesized in moderate yields (57–67%) by Groebke–Blackburn–Bienaymé reaction (GBBR) under catalyst and solvent green conditions. The molecules synthesized containing triphenylamine and imidazo[1,2-a]pyridines cores which are considered a privileged cores exhibited fluorescence and medicinal properties. Full article
Proceeding Paper
Synthesis of Amino Alcohols from Eugenol and Their Insecticidal Activity against Sf9 Cell Line
Chem. Proc. 2021, 3(1), 62; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08337 - 14 Nov 2020
Viewed by 89
Abstract
Eugenol is a major constituent of clove essential oil with interesting biological activity, namely antimicrobial and antioxidant. Structural changes of eugenol are a useful strategy in order to improve biological activity and at the same time obtain new analogues with reduced side effects. [...] Read more.
Eugenol is a major constituent of clove essential oil with interesting biological activity, namely antimicrobial and antioxidant. Structural changes of eugenol are a useful strategy in order to improve biological activity and at the same time obtain new analogues with reduced side effects. In this work, a series of amine nucleophiles were reacted with eugenol epoxide so as to obtain the corresponding amino alcohols, considering their potential as biopesticides. These eugenol amino alcohols were evaluated against insect cells, specifically the Sf9 cell line. Full article
Proceeding Paper
Evaluation of Fluorescent Staining Capacity of Two New Nile Blue Analogues
Chem. Proc. 2021, 3(1), 63; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08383 - 14 Nov 2020
Viewed by 64
Abstract
Benzophenoxazine fluorophores, including derivatives of Nile Blue, one of the best known in this family of compounds, have been used as histological stains due to their optical properties in the NIR region and stability. Given their potential, the synthesis of two new Nile [...] Read more.
Benzophenoxazine fluorophores, including derivatives of Nile Blue, one of the best known in this family of compounds, have been used as histological stains due to their optical properties in the NIR region and stability. Given their potential, the synthesis of two new Nile Blue derivatives with different substituents on the amines of the positions 5 and 9 was performed, with the introduction of a sulfonamide group in one of the compounds. Photophysical properties of the compounds were evaluated in acidified ethanol and aqueous solution at physiological pH. The fluorescent staining capacity was evaluated by staining Saccharomyces cerevisiae with the compounds, followed by fluorescence microscopy. Full article
Proceeding Paper
Design, Synthesis and Bioactivity of Benzimidazole–2–Carbamates as Soil–Borne Anti–Fungal Agents †,‡
Chem. Proc. 2021, 3(1), 64; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08093 - 13 Nov 2020
Viewed by 129
Abstract
The design and synthesis of new, safe and potent molecules to apply against soil-borne pathogens is a critical goal for organic and bio-medicinal chemists. Herein, we designed and synthesized a series of benzimidazole-based carbamate derivatives (7a–f), as soil-borne anti-fungals. The derivatives 7a–f were [...] Read more.
The design and synthesis of new, safe and potent molecules to apply against soil-borne pathogens is a critical goal for organic and bio-medicinal chemists. Herein, we designed and synthesized a series of benzimidazole-based carbamate derivatives (7a–f), as soil-borne anti-fungals. The derivatives 7a–f were all synthesized in multi-step reactions with acceptable yields. The structures of 7a–f were all identified and characterized using 1H-NMR, IR, HRMS, and melting point calculations. The final compounds were tested on five soil-borne pathogens. The results of various bio-assays showed that compounds 7a-3, 7a-2, 7b-2, 7a-1 and 7b-1 significantly affected the growth of Pythium aphanidermatum, a serious pathogen affecting vegetable crops worldwide. Compounds 7a-1 and 7b-1 were the most efficacious, which resulted in a 96% growth inhibition in Pythium at 100 mg L−1. In conclusion, we reported the potent carbamate derivatives as soil-borne anti-fungals, and believe that the synthesis of more derivatives related to the current scaffold would be beneficial. Full article
Proceeding Paper
A meso-Triphenylamine-BODIPY Derivative for the Optical Chemosensing of Metal Ions
Chem. Proc. 2021, 3(1), 65; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08291 - 14 Nov 2020
Viewed by 99
Abstract
The design and synthesis of organic molecules for recognition of biologically/environmentally important metal ions has emerged as a highly regarded research field. The BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) core is a versatile signaling molecule that can be fine-tuned with functional groups to create selective [...] Read more.
The design and synthesis of organic molecules for recognition of biologically/environmentally important metal ions has emerged as a highly regarded research field. The BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) core is a versatile signaling molecule that can be fine-tuned with functional groups to create selective binding sites to improve its optical properties. As an extension of the work developed in our research group, we report the synthesis and characterization of a BODIPY functionalized with triphenylamino and a formyl group at the meso and 2-position, respectively, for the highly selective detection of Cu2+ and Fe3+. The preliminary study of the BODIPY derivative as optical chemosensor was carried out in acetonitrile solution in the presence of different cations, and interactions with Cu2+ and Fe3+ induced a perceptible color change. UV-visible titrations showed changes in the absorption spectra upon the addition of three equivalents of each cation, with the appearance of a new absorption band at 693 nm. Full article
Proceeding Paper
New Heterocyclic Derivatives of Usnic Acid
Chem. Proc. 2021, 3(1), 66; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08459 - 16 Nov 2020
Viewed by 354
Abstract
New heterocyclic derivatives of usnic acid have been obtained by the reaction of bromousnic acid with CS2-based nucleophiles. A series of compounds with dithiolane, 1,3,4-thiadiazine, and thiophene fragments was synthesized. Full article
Proceeding Paper
Rational Design, Synthesis, and In-Silico Evaluation of Homologous Local Anesthetic Compounds as TASK-1 Channel Blockers
Chem. Proc. 2021, 3(1), 67; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08416 - 14 Nov 2020
Viewed by 114
Abstract
Advances in different technological and scientific fields have led to the development of tools that allow the design of drugs in a rational way, using defined therapeutic targets, and through simulations that offer a molecular view of the ligand–receptor interactions, giving precise information [...] Read more.
Advances in different technological and scientific fields have led to the development of tools that allow the design of drugs in a rational way, using defined therapeutic targets, and through simulations that offer a molecular view of the ligand–receptor interactions, giving precise information for the design and synthesis of new compounds. Ion channels are of great relevance as therapeutic targets since they play roles in different pathologies. Several ion channels are expressed in the atria and constitute a therapeutic target for the treatment of atrial fibrillation (AF), the most common type of arrhythmia and an important risk factor for an increase in cerebrovascular illness. The action potential (AP) of a cardiomyocyte is initiated by the depolarization of the membrane through the inflow of sodium (Na+). The repolarization currents are realized by different potassium (K+) channels. Background currents of TASK-1 channels can also contribute to AP, and TASK-1 channel blockers could become innovative strategies against AF. The compounds used in this study were based on local anesthetic (LAs)-type compounds that have been shown to be TASK-1 channel blockers, such as lidocaine, ropivacaine, and bupivacaine, and that have antiarrhythmic capacity, becoming potentially effective drugs for the treatment of AF. The main objective of this study was, based on the common characteristics of LAs, to propose the synthesis of analogues of LAs and evaluate them in silico as TASK-1 channel blockers. Full article
Proceeding Paper
Study of 1,2,4-triazole-3(5)-thiol Behavior in Reactions with 1-phenyl-1H-pyrrole-2,5-dione Derivatives and 3-bromodihydrofuran-2(3H)-one and Antimicrobial Activity of Products
Chem. Proc. 2021, 3(1), 68; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08419 - 14 Nov 2020
Viewed by 122
Abstract
In present work we report our studies of the interaction of 1-phenyl-1H-pyrrole-2,5-dione derivatives (N-arylmaleimides) and 3-bromodihydrofuran-2(3H)-one (α-bromo-γ-butyrolactone) as possible [C2]2+ synthons with 1,2,4-triazole-3(5)-thiole targeting on synthesis of novel 5-substituted thiazolo[3,2-b][1,2,4]triazole-6(5H)-ones. According to [...] Read more.
In present work we report our studies of the interaction of 1-phenyl-1H-pyrrole-2,5-dione derivatives (N-arylmaleimides) and 3-bromodihydrofuran-2(3H)-one (α-bromo-γ-butyrolactone) as possible [C2]2+ synthons with 1,2,4-triazole-3(5)-thiole targeting on synthesis of novel 5-substituted thiazolo[3,2-b][1,2,4]triazole-6(5H)-ones. According to obtained results was establish that in above-mentioned interactions (conditions: convenient heating, range of solvents/reaction time) the thiol-ene click (for N-arylmaleimides) and SN (for α-bromo-γ-butyrolactone) processes take place, but not [2+3]-cyclocondensation reaction. The structure of compounds was studied using 1H, 13C NMR spectroscopy, LC-MS spectrometry, and X-ray analysis. The prescreening of antimicrobial activity for synthesized compounds was performed against Gram-positive and Gram-negative bacteria, as well as yeasts. Full article
Proceeding Paper
Synthesis and Antioxidant Activity of 2-Amino-5-R-1,3,4-Oxadiazoles with Hindered Phenol Fragments
Chem. Proc. 2021, 3(1), 69; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08407 - 14 Nov 2020
Cited by 1 | Viewed by 110
Abstract
Compounds with hindered phenolic moiety are known to be effective inhibitors of oxidative processes in different materials; moreover, a number of phenols show a wide spectrum of biological activity. At the same time, five-membered heterocycles exhibit unique properties, including antioxidant activity. One of [...] Read more.
Compounds with hindered phenolic moiety are known to be effective inhibitors of oxidative processes in different materials; moreover, a number of phenols show a wide spectrum of biological activity. At the same time, five-membered heterocycles exhibit unique properties, including antioxidant activity. One of the ways to create new effective antioxidants with a set of useful properties is to combine hindered phenol and a heterocyclic fragment in one molecule. In this work, new 1-acyl-4-R-thiosemicarbazides were obtained during a reaction between 3-(4-hydroxy-3,5-di-tert-butylphenyl)propanoic acid hydrazide and a number of isothiocyanates. 2-Amino-5-R-1,3,4-oxadiazoles were prepared in good yields by heterocyclization of 1-acyl-4-R-thiosemicarbazides in presence of iodoxybenzoic acid and triethylamine. The antioxidant activity of 1,3,4-oxadiazoles was studied in vitro and was found to be higher than that of 4-methyl-2,6-di-tert-butylphenol. Full article
Proceeding Paper
Direct Arylation-Based Synthesis of Carbazoles Using an Efficient Palladium Nanocatalyst under Microwave Irradiation
Chem. Proc. 2021, 3(1), 70; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08314 - 14 Nov 2020
Viewed by 92
Abstract
Herein, an eco-friendly palladium-catalyzed tandem reaction for the one-pot synthesis of carbazoles under microwave irradiation is reported. This approach involves an amination and a direct arylation from available and inexpensive anilines and 1,2-dihaloarenes. For the development of this purpose, a novel recoverable palladium [...] Read more.
Herein, an eco-friendly palladium-catalyzed tandem reaction for the one-pot synthesis of carbazoles under microwave irradiation is reported. This approach involves an amination and a direct arylation from available and inexpensive anilines and 1,2-dihaloarenes. For the development of this purpose, a novel recoverable palladium nanocatalyst supported on a green biochar under ligand-free conditions is used. Compared with other existing palladium-based protocols, the present synthetic methodology shows a drastic reduction in reaction times and excellent compatibility with different functional groups, allowing to obtain a small library of carbazoles with high yields and regioselectivity. The novel heterogeneous palladium nanocatalyst can be recycled and reused up to five times without significant loss activity. Full article
Proceeding Paper
Chemical Synthesis and Hemi-Synthesis of Novel Benzimidazole Derivatives Using Microwave-Assisted Process: Chemical Characterization, Bioactivities and Molecular Docking
Chem. Proc. 2021, 3(1), 71; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08306 - 14 Nov 2020
Viewed by 152
Abstract
Benzimidazole derivatives represent a class of heterocyclic compounds that exhibit a wide range of pharmaceutical properties. The present study aimed to investigate the in-vitro antioxidant and antimicrobial activities of newly synthesized benzimidazole derivatives. Compound 1b (2-(1H-1,3-benzodiazol-2-yl) phenol) was synthesized by reacting o-phenylenediamine (OPA) [...] Read more.
Benzimidazole derivatives represent a class of heterocyclic compounds that exhibit a wide range of pharmaceutical properties. The present study aimed to investigate the in-vitro antioxidant and antimicrobial activities of newly synthesized benzimidazole derivatives. Compound 1b (2-(1H-1,3-benzodiazol-2-yl) phenol) was synthesized by reacting o-phenylenediamine (OPA) with chemical salicylaldehyde, while compounds 2b (2-(2-[(1E)-2-phenylethenyl]-1H-1,3-benzodiazole) and 3b (2-[(1E)-2,6-dimethylhepta-1,5-dien-1-yl]-1H-1,3-benzodiazole) were obtained through a hemi-synthesis process of, respectively, the cinnamon (cinnamaldehyde, 90.54%) and lemongrass (cis-citral, 43.9%) essential oils previously characterized by GC/MS. Compounds 4b (2-phenyl-1H-benzimidazole) and 5b (5-(1H-benzimidazol-2-yl)benzene-1,2,3-triol) were synthesized with a click chemistry method by reacting the OPA with benzoic acid and gallic acid directly in ethanol under microwave irradiation (MW) at 400 MHz. The structure/purity of the synthesized compounds was clarified by spectroscopy, ATR-FTIR and NMR 1H. Compounds 1b5b were screened for their antioxidant activity by using four complementary in-vitro assays: DPPH scavenging activity, ferric ion reducing power, β-carotene bleaching inhibition, and Thiobarbituric Acid Reactive Substance Assay (TBARS) formation inhibition. All the tested compounds showed antioxidant potential, with varying performance. Antimicrobial activity was investigated against American Type Culture Collection (ATCC) strains (three Gram- bacteria: Escherichia coli, Salmonella typhi, and Pseudomonas aeruginosa; one Gram+ bacteria: Staphylococcus aureus, and one yeast strain: Candida albicans) through the determination of the Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) by using the microdilution method and rapid colorimetric test of p-iodonitrotetrazolium chloride (INT). Compound 5b exhibited the highest potential, especially against S. aureus (MIC = 0.156 mg·mL−1) followed by S. typhi and C. albicans (MIC = 0.3125 mg·mL−1) and then by E. coli and P. aeruginosa. Compound 1b also showed great potential against S. aureus and C. albicans (MIC ˂ 0.3125 mg·mL−1), followed by E. coli and S. typhi (MIC = 0.3125 mg·mL1) and P. aeruginosa (MIC = 0.625 mg·mL−1). Further molecular docking was conducted using AutoDock Vina 1.1.2 software on S. aureus thymidylate kinase (TMK) protein to highlight the structure–activity relationship of the potent molecules. Full article
Proceeding Paper
New BODIPY Dye with a Large Stokes Shift for Biopolymer Labelling
Chem. Proc. 2021, 3(1), 72; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08304 - 14 Nov 2020
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Abstract
As the most abundant protein with a variety of physiological functions, human serum albumin (HSA) has been used extensively for the delivery and improvement of therapeutic molecules. Thiolactone chemistry provides a powerful tool to prepare albumin-based multimodal imaging probes and agents for boron [...] Read more.
As the most abundant protein with a variety of physiological functions, human serum albumin (HSA) has been used extensively for the delivery and improvement of therapeutic molecules. Thiolactone chemistry provides a powerful tool to prepare albumin-based multimodal imaging probes and agents for boron neutron capture therapy (BNCT). For this purpose, boron containing 4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) dye was designed and synthesized. BODIPY dyes are photostable neutral derivatives of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene. These are widely used as chemosensors, laser materials and molecular probes. At the same time, BODIPY dyes, like most other fluorophores, have small or moderate Stokes shifts. Large Stokes shifts are preferred for fluorophores because of higher sensitivity of such probes and sensors. We succeeded in performing an annulation of pyrrole ring with coumarin heterocyclic system and achieved a remarkable difference in absorption and emission maximum of obtained fluorophore up to 100 nm. Moreover, this BODIPY dye was equipped with a linker arm and was functionalized with a maleimide residue specifically reactive towards thiol groups of proteins. The released sulfhydryl groups of the homocysteine functional handle in thiolactone modified HSA was labeled with BODIPY dye to prepare a labeled albumin-BODIPY dye conjugate confirmed by MALDI-TOF-MS, UV-vis and fluorescent emission spectra. The cytotoxicity of HSA conjugate was evaluated by MTT assay in cell lines MCF-7 and T98G. This is the basis for a novel BODIPY dye -albumin theranostic for BNCT. These results provide further impetus to develop derivatives of HSA for delivery of boron to cancer cells. Full article
Proceeding Paper
Interactions between Isoniazid and α-Hydroxycarboxylic Acids
Chem. Proc. 2021, 3(1), 73; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08355 - 14 Nov 2020
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Abstract
The present study refers to the preparation of isonicotinic acid hydrazide (isoniazid (INH)) cocrystals with two α-hydroxycarboxylic acids. The interaction of glycolic acid (H2ga) or dl-mandelic acid (H2ma) resulted in the formation of cocrystals, or salts of composition, as [...] Read more.
The present study refers to the preparation of isonicotinic acid hydrazide (isoniazid (INH)) cocrystals with two α-hydroxycarboxylic acids. The interaction of glycolic acid (H2ga) or dl-mandelic acid (H2ma) resulted in the formation of cocrystals, or salts of composition, as isoniazid−glycolic acid cocrystal (INH)·(H2ga) (1) and isoniazid−dl-mandelic acid salt cocrystal [HINH]+[Hma]·(H2ma) (2), when reacted with isoniazid. An N’-(propan-2-ylidene)isonicotinic hydrazide hemihydrate, (pINH)·1/2(H2O) (3), was also prepared by condensation of isoniazid with acetone in the presence of glycolic acid. The prepared compounds were well characterized by elemental analysis and spectroscopic methods, and their three-dimensional molecular structure was determined by single-crystal X-ray crystallography. Hydrogen bonds involving carboxylic acid occur consistently with the pyridine ring N atom of the isoniazid and its derivatives. The remaining hydrogen-bonding sites on the isoniazid backbone vary on the basis of the steric influences of the derivative group. These are contrasted in each of the molecular systems. Full article
Proceeding Paper
One-Pot Selective Functionalization of Polysaccharides with Urea
Chem. Proc. 2021, 3(1), 74; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08346 - 14 Nov 2020
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Abstract
Natural polysaccharides are polymers composed of monosaccharide units bound together by glycosidic linkages. In their native form, these polymers may not be able to provide all the desired properties for a particular application. Thus, the functionalization of their reactive hydroxyl groups would change [...] Read more.
Natural polysaccharides are polymers composed of monosaccharide units bound together by glycosidic linkages. In their native form, these polymers may not be able to provide all the desired properties for a particular application. Thus, the functionalization of their reactive hydroxyl groups would change their surface properties. In this work, we evaluated the derivatization of OH groups of maltodextrin polysaccharide with urea. Through a one-pot selective procedure carried out at room temperature for 3 h, urea united at maltodextrin through covalent bonding was obtained. The results show that after functionalization with urea, the pH and solubility in polar solvents of the new material increased. Derivatization of maltodextrin with urea confers stability, and terminal amide groups on the surface of this material represent a versatile reactive functional group for conjugation with other molecules for potential applications in the development of new materials. Full article
Proceeding Paper
Identification of Natural Products for the Treatment of Alzheimer’s Disease: 3D Similarity Search
Chem. Proc. 2021, 3(1), 75; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08341 - 14 Nov 2020
Viewed by 110
Abstract
Glycogen synthase kinase-3 (GSK-3), one of the main tau kinases involved in a variety of cellular processes, has been evidenced as a promising target for Alzheimer’s disease (AD) treatment. In recent years, great efforts have been made to discover new molecules with an [...] Read more.
Glycogen synthase kinase-3 (GSK-3), one of the main tau kinases involved in a variety of cellular processes, has been evidenced as a promising target for Alzheimer’s disease (AD) treatment. In recent years, great efforts have been made to discover new molecules with an enhanced profile that inhibit GSK-3 and display efficacy in AD treatment. SAR502250, a newly discovered selective GSK-3 inhibitor with AD therapeutic potential, represents a good alternative to design future specific inhibitors against this condition. SAR502250 was used as a query in a 3D similarity search on the SPECS database to select new natural compounds as possible GSK-3 inhibitors. According to ShapeTanimoto, TanimotoCombo, and ComboScore matrics, the first 10 SPECS natural compounds were selected and structurally analyzed. The ADME (Absorption, Distribution, Metabolism, and Excretion), physicochemical parameters, and toxicity-related risk profiles of the selected natural compounds were also investigated. The 3D similarity results in conjunction with pharmaceutical profiles revealed the potential use of natural compounds as GSK-3 inhibitors for Alzheimer’s disease therapy. Full article
Proceeding Paper
Insight into the Influence of the Chiral Molecular Symmetry on the Chiroptics of Fluorescent BINOL-Based Boron Chelates
Chem. Proc. 2021, 3(1), 76; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08308 - 14 Nov 2020
Viewed by 149
Abstract
The prominent influence of the molecular symmetry, as defined by the symmetry point group, on the chiroptical behavior (electronic circular dichroism and, especially, circularly polarized luminescence) of simple fluorescent boron chelates (BODIPY and related BOPHY analogues) is studied and discussed. It is shown [...] Read more.
The prominent influence of the molecular symmetry, as defined by the symmetry point group, on the chiroptical behavior (electronic circular dichroism and, especially, circularly polarized luminescence) of simple fluorescent boron chelates (BODIPY and related BOPHY analogues) is studied and discussed. It is shown that increasing the dye symmetry by means of the D3 chiral symmetry group is a workable design option to enhance the level of differential emission of right- and left-circularly polarized light in BODIPY dyes and related emitters, and that the influence of the level of symmetry is stronger than the influence of the higher number of chiral moieties perturbing the acting achiral chromophore. Full article
Proceeding Paper
Lead Finding from Plant Cymbopogon Citratus with Immunomodulator Potentials through in Silico Methods
Chem. Proc. 2021, 3(1), 77; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08302 - 14 Nov 2020
Viewed by 81
Abstract
The aim of this study was to examine the correlation between immunomodulators and the molecular properties of the Cymbopogon citratus derivatives in search of a lead compound through molinspiration cheminformatics software. Ten naturally occurring derivatives of Cymbopogon citratus were selected for bioactivity prediction [...] Read more.
The aim of this study was to examine the correlation between immunomodulators and the molecular properties of the Cymbopogon citratus derivatives in search of a lead compound through molinspiration cheminformatics software. Ten naturally occurring derivatives of Cymbopogon citratus were selected for bioactivity prediction and drug likeness score on the basis of Lipinski’s rule. All of the compounds fulfilled Lipinski’s rule as their Milog P score was below 5, suggesting these compounds show good permeability across cell membranes. All the screened compounds had minimum or no violations of the Lipinski rule. Cymbopogon citratus and its derivatives showed a good bioactivity score for drug targets including nuclear receptor ligand, protease inhibitor and enzyme inhibition and thus are expected to have excellent pharmacological activity in vivo. The results of this study justify their topical application as immunomodulators but some structural modifications in order to make the compound more polar would definitely improve oral bioavailability and thus the usefulness and therapeutic efficacy of Cymbopogon citratus. All the Cymbopogon citratus derivatives are predicted to be orally active and are considered as potential candidates for further research as their bioactivity score due to high affinity for various drug targets was better than the standard as well as among other tested compounds. Full article
Proceeding Paper
Synthesis and Quantum-Chemical Studies of New Hybrid Heterocyclic Molecules Derived from 3-(Thiocyanatoacetyl)Coumarin
Chem. Proc. 2021, 3(1), 78; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08104 - 13 Nov 2020
Viewed by 65
Abstract
3-(Thiocyanatoacetyl)coumarin, prepared by a reaction of 3-(bromoacetyl)coumarin with KSCN, reacts with primary aryl amines to give new hybrid heterocyclic products, 3-(3-aryl-2-imino-2,3-dihydrothiazol-4-yl)-2Н-chromen-2-ones. The structures and conformational features of the products have been studied by the B3LYP-D3/6-311G(d,p) method. Full article
Proceeding Paper
Synthesis and Characterization of a meso-Anthracene-BODIPY Derivative for Colorimetric Recognition of Cu2+ and Fe3+
Chem. Proc. 2021, 3(1), 79; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08292 - 14 Nov 2020
Viewed by 94
Abstract
Ions exist widely in biological and environmental media, and the scarcity or excess of these species can have adverse consequences. BODIPY dyes appear as heterocyclic organic compounds capable of recognizing metal ions in solution and in cells, through optical signals (colorimetric and/or fluorimetric), [...] Read more.
Ions exist widely in biological and environmental media, and the scarcity or excess of these species can have adverse consequences. BODIPY dyes appear as heterocyclic organic compounds capable of recognizing metal ions in solution and in cells, through optical signals (colorimetric and/or fluorimetric), and their photophysical properties can be adjusted through the functionalization of the BODIPY core. In continuation of the work developed recently, our research group reports the synthesis of a meso-anthracene-BODIPY derivative and the respective characterization by 1H and 13C nuclear magnetic resonance (NMR) and UV-Vis absorption spectroscopies. The preliminary study of the chemosensory capacity of the BODIPY derivative was also carried out in the presence of several cations in acetonitrile solution, which shows a selective colorimetric response for Cu2+ and Fe3+. Full article
Proceeding Paper
Synthesis and Structural Characterization of Imidazolium-Based Dicationic Ionic Liquids
Chem. Proc. 2021, 3(1), 80; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08389 - 14 Nov 2020
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Abstract
Dicationic ionic liquids present a novel class of ionic liquids composed of dication and two monoanions; the latter have shown an increasing interest in recent years and are used in many applications. Compared to conventional ionic liquids, the physicochemical properties of dicationic ionic [...] Read more.
Dicationic ionic liquids present a novel class of ionic liquids composed of dication and two monoanions; the latter have shown an increasing interest in recent years and are used in many applications. Compared to conventional ionic liquids, the physicochemical properties of dicationic ionic liquids can be set by modifying the languor and the type of chains linking the cationic heads as well as the type of cation. In this work, we present the synthesis of three dicationic ionic liquids based on imidazolium with two steps; the first of which is a quaternization reaction leading to the formation of dicationic ionic liquids with the iodide ion. The characterization of these organic salts was carried out by magnetic resonance spectroscopy, allowing a better identification of the products obtained. Full article
Proceeding Paper
Lactamomethylation of Phenols: Synthesis, In Silico Study of Reactivity and Possible Applications
Chem. Proc. 2021, 3(1), 81; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08408 - 14 Nov 2020
Viewed by 114
Abstract
Lactamomethylation of phenols with various substituents was provided by pyrrolidone, valerolactam, caprolactam, and 4-phenylpyrrolidone derivatives. The structures of the target compounds were confirmed by IR and NMR study. The behavior of alkylphenols (2,4-di-tert-butyl- and thymol), diphenols (catechol and hydroquinone), formylphenol (vanillin), and hydroxybenzoic [...] Read more.
Lactamomethylation of phenols with various substituents was provided by pyrrolidone, valerolactam, caprolactam, and 4-phenylpyrrolidone derivatives. The structures of the target compounds were confirmed by IR and NMR study. The behavior of alkylphenols (2,4-di-tert-butyl- and thymol), diphenols (catechol and hydroquinone), formylphenol (vanillin), and hydroxybenzoic acids (salicylic and resorcylic) in this reaction was compared by quantum-chemical calculations. For several compounds, the energy of dissociation of the ArO-H bond was calculated by quantum-chemical method to reveal their possible antioxidant activity. In addition, the ability of synthesized compounds to destruct cumene hydroperoxide was studied. It was estimated that 1-(4-hydroxy-5-isopropil-2-methylbenzyl)azepan-2-one and 1-(4-hydroxy-5-isopropil-2-methylbenzyl)pyrrolidin-2-one possess the best antioxidant effect, comparable to the one of industrial additive butylated hydroxytoluene (BHT). Full article
Proceeding Paper
On the Use of CeCl3.7H2O as a Catalyst for the Synthesis of Hydrazones Derived from Aromatic Aldehydes and Ketones
Chem. Proc. 2021, 3(1), 82; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08095 - 13 Nov 2020
Viewed by 92
Abstract
Hydrazonation of acetophenones and benzaldehydes under CeCl3 assistance was evaluated. The transformations entailed the use of the respective hydrazines (H2N–NH2.HCl, Me2N–NH2, or Ph2N–NH2.HCl) and CeCl3.7H2O (2–5 [...] Read more.
Hydrazonation of acetophenones and benzaldehydes under CeCl3 assistance was evaluated. The transformations entailed the use of the respective hydrazines (H2N–NH2.HCl, Me2N–NH2, or Ph2N–NH2.HCl) and CeCl3.7H2O (2–5 mol %). The use of different solvents in a model reaction between 3,4-dimethoxybenzaldehyde and N,N-dimethylhydrazine was studied. Full article
Proceeding Paper
Synthesis of Epoxyisoindolinones via Microwave-Assisted Ugi-4CR/Intramolecular-Diels-Alder Reaction
Chem. Proc. 2021, 3(1), 83; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08425 - 14 Nov 2020
Viewed by 108
Abstract
A series of epoxyisoindolinones were synthesized by microwave-assisted post-IMCR transformation-based domino strategy via the Ugi-4CR/Intramolecular-Diels-Alder (U-4CR/IMDA) sequence under mild, solvent-, catalyst-free ecofriendly conditions, and orthogonal-bifunctional components. Epoxyisoindolinones are a privileged core of high interest in medicinal chemistry mainly for its anticancer activity in [...] Read more.
A series of epoxyisoindolinones were synthesized by microwave-assisted post-IMCR transformation-based domino strategy via the Ugi-4CR/Intramolecular-Diels-Alder (U-4CR/IMDA) sequence under mild, solvent-, catalyst-free ecofriendly conditions, and orthogonal-bifunctional components. Epoxyisoindolinones are a privileged core of high interest in medicinal chemistry mainly for its anticancer activity in several cell lines. Full article
Proceeding Paper
Ecotoxicity of Mixtures of IL and Lithium Salt
Chem. Proc. 2021, 3(1), 84; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08361 - 14 Nov 2020
Cited by 1 | Viewed by 99
Abstract
The applicability of ionic liquids (IL) has been increased during the last years and even new opportunities are becoming a reality, i.e., mixtures of pure IL and inorganic salt as electrolytes for smart electrochemical devices. In this work, the ecotoxicity of two protic [...] Read more.
The applicability of ionic liquids (IL) has been increased during the last years and even new opportunities are becoming a reality, i.e., mixtures of pure IL and inorganic salt as electrolytes for smart electrochemical devices. In this work, the ecotoxicity of two protic ILs (Ethylammonium nitrate and Ethylimidazolium nitrate) and one aprotic IL (butylmethylpyrrolidinium bis(trifluoroomethylsulfonyl)imide) doped with the corresponding Lithium salt was tested towards changes on the bioluminescence of the bacteria Aliivibrio fischeri, using the Microtox® standard toxicity test. Half maximal effective concentration (EC50) of these mixtures was determined over three standard periods of time and compared with the corresponding values to pure ILs. Full article
Proceeding Paper
Ecotoxicological Evaluation of Ethylammonium Nitrate and Aluminium Salt Mixture
Chem. Proc. 2021, 3(1), 85; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08364 - 14 Nov 2020
Viewed by 104
Abstract
The ecotoxicity of a mixture of the ionic liquid ethylammonium nitrate (EAN) and aluminum nitrate salt (Al(NO3)3), as well as the corresponding pure components, was studied in this work. This mixture is of singular interest as electrolytes in electrochemical [...] Read more.
The ecotoxicity of a mixture of the ionic liquid ethylammonium nitrate (EAN) and aluminum nitrate salt (Al(NO3)3), as well as the corresponding pure components, was studied in this work. This mixture is of singular interest as electrolytes in electrochemical applications and data on the effects of mixture and components on the environment can hardly be found in the literature. Changes in the bioluminescence of the Aliivibrio fischeri (Beijerinck) Urbanczyk bacteria, determined through a Microtox® test, and microbial activity, measured by microcalorimetry, of two soils with different organic matter contents when exposed to solutions of different concentrations of these compounds were analyzed. Full article
Proceeding Paper
Synthesis of (2S,3S)-3-Aroyl Pyroglutamic Acid Amides
Chem. Proc. 2021, 3(1), 86; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08377 - 14 Nov 2020
Viewed by 71
Abstract
A new methodology for the asymmetric synthesis of enantiomerically enriched 3-aroyl pyroglutamic acid derivatives has been developed through effective 5-exo-tet cyclization of N-chloroacetyl aroylalanines. The three-step sequence starts with the synthesis of N-substituted (S,S)-2-amino-4-aryl-4-oxobutanoic acids [...] Read more.
A new methodology for the asymmetric synthesis of enantiomerically enriched 3-aroyl pyroglutamic acid derivatives has been developed through effective 5-exo-tet cyclization of N-chloroacetyl aroylalanines. The three-step sequence starts with the synthesis of N-substituted (S,S)-2-amino-4-aryl-4-oxobutanoic acids via highly diastereoselective tandem aza-Michael addition and crystallization-induced diastereomer transformation (CIDT). Their N-chloroacetylation followed by base-catalyzed cyclization and ultimate acid-catalyzed removal of chiral auxiliary without loss of stereochemical integrity furnishes the target substituted pyroglutamic acids. Finally, several series of their benzyl amides were prepared as 3-aroyl analogs of known P2X7 antagonists. Full article
Proceeding Paper
One-Step Synthesis of 5a,11a-Janusene Imide Employing 2,3-Dibromo-N-methylmaleimide as Acetylene Equivalent
Chem. Proc. 2021, 3(1), 87; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08426 - 14 Nov 2020
Viewed by 74
Abstract
Synthesis of janusene (5,5a,6,11,11a,12-hexahydro-5,12:6,11-di-o-benzenonaphthacene) requires several reaction steps, starting from anthracene. In this account, a one-pot, three-step synthesis of janusene N-methyl-5a,11a-dicarboximide employing 2,3-dibromo-N-methylmaleimide as an acetylene equivalent is described. This thermal reaction is a simple synthetic procedure in [...] Read more.
Synthesis of janusene (5,5a,6,11,11a,12-hexahydro-5,12:6,11-di-o-benzenonaphthacene) requires several reaction steps, starting from anthracene. In this account, a one-pot, three-step synthesis of janusene N-methyl-5a,11a-dicarboximide employing 2,3-dibromo-N-methylmaleimide as an acetylene equivalent is described. This thermal reaction is a simple synthetic procedure in comparison to sequential-multi step [4+2] cycloaddition routes. Here, 2,3-dibromo-N-methylmaleimide acts effectively as a ‘molecular glue’, bridging two anthracene molecules together. Full article
Proceeding Paper
Heterocyclic Aldehydes Based on Thieno[3,2-b]thiophene Core: Synthesis and Preliminary Studies as Ion Optical Chemosensors
Chem. Proc. 2021, 3(1), 88; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08092 - 13 Nov 2020
Viewed by 124
Abstract
Heterocyclic aldehydes show a variety of optical properties and the versatility of their reactivity allows them to yield a wide range of more complex compounds, with application in areas such as medicinal, materials and supramolecular chemistry. The biological and environmental relevance of certain [...] Read more.
Heterocyclic aldehydes show a variety of optical properties and the versatility of their reactivity allows them to yield a wide range of more complex compounds, with application in areas such as medicinal, materials and supramolecular chemistry. The biological and environmental relevance of certain molecules and ions turns them into targets for the design of molecular recognition systems. Recently, heterocyclic aldehydes have been reported in the literature as ion chemosensors. Following the group’s work on optical chemosensors, for the detection and quantification of ions and molecules with environmental and medicinal relevance, this work reports the synthesis and characterization of two heterocyclic aldehydes based on the thieno[3,2-b]thiophene core, by Suzuki coupling, as well as the synthesis of the corresponding precursors. Preliminary chemosensory studies for the synthesized heterocyclic aldehydes in the presence of selected cations were also performed, in solution, in order to determine their potential application as optical chemosensors. Full article
Proceeding Paper
ZnFe2O4@dimethylglyoxime: Preparation and Catalyst Application in the Synthesis of 2-Amino-tetrahydro-4H-chromene-3-carbonitrile Derivatives
Chem. Proc. 2021, 3(1), 89; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08287 - 14 Nov 2020
Viewed by 85
Abstract
Hybrid materials constructed from two or more constituents provide new features and distinctive applications which not found in the single-part material. Spinel ferrites with the general formula of AB2O4, where A denotes divalent ions and B represents trivalent ions, [...] Read more.
Hybrid materials constructed from two or more constituents provide new features and distinctive applications which not found in the single-part material. Spinel ferrites with the general formula of AB2O4, where A denotes divalent ions and B represents trivalent ions, appeared as efficient catalysts for the synthesis of organic compounds. These magnetic nanoparticles have both the Lewis acid and the Lewis base sites in their structure. In the present study, ZnFe2O4 was prepared and modified with dimethylglyoxime to obtain a magnetic ZnFe2O4@dimethylglyoxime hybrid catalyst. Dimethylglyoxime is a dibasic acid substance that has been used as a chelating agent for divalent metal ions due to containing two nitrogen atoms and hydroxyl groups. Surface modification of zinc ferrite with this dibasic acid substance produced a bifunctional hybrid catalyst with increased catalytic active sites. In the next step, a prepared catalyst was applied in the synthesis of 2-amino-tetrahydro-4H-chromene-3-carbonitrile derivatives by condensation of aromatic aldehydes, malononitrile and dimedone in ethanol at room temperature. The present method offers advantages such as simple procedure, mild reaction condition, short reaction times and retrievable catalyst. Full article
Proceeding Paper
Diplodomica II. Repugnatorial Secretion of Ecuadorian Endemic Millipede Rhinocricus sp. (Diplopoda, Spirobolida, Rhinocricidae) from Orellana Province, Amazonia, Ecuador
Chem. Proc. 2021, 3(1), 90; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08435 - 14 Nov 2020
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Abstract
Millipedes (Myriapoda: Diplopoda) represents one of the oldest and most evolutionary successful classes of invertebrates. The order Spirobolida is dominantly tropical, and the family Rhinocricidae is widely distributed in the Ecuadorian edaphic fauna inhabiting the Amazonia region. The millipedes collected were stimulated mechanically, [...] Read more.
Millipedes (Myriapoda: Diplopoda) represents one of the oldest and most evolutionary successful classes of invertebrates. The order Spirobolida is dominantly tropical, and the family Rhinocricidae is widely distributed in the Ecuadorian edaphic fauna inhabiting the Amazonia region. The millipedes collected were stimulated mechanically, and an ejected repugnatorial fluid was subjected to structural analysis. The analysis of the defensive–repugnatorial secretion of the endemic millipede Rhinocricus sp., inhabiting in the Amazonian region of Orellana, Republic of Ecuador, and chemical evidence (chromogenic reactions: KI starch paper and rodanine test in aqueous ammonia) as well, revealed the quinonoide composition of the secretion. We identified 2-methyl-3-methoxy-1,4-benzoquinone as an active major component. Full article
Proceeding Paper
Influence of Nonpolar Medium on Antioxidant Capacity of Bergaptol and Xanthotoxol—Kinetic DFT Study
Chem. Proc. 2021, 3(1), 91; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08100 - 13 Nov 2020
Viewed by 98
Abstract
Within this study, the antioxidant capacity of bergaptol (BER) and xanthotoxol (XAN) in a nonpolar environment (benzene) was investigated against the reference standard trolox (Tx). The ability to inactivate HO radicals from the kinetic aspect was examined through hydrogen atom transfer (HAT), [...] Read more.
Within this study, the antioxidant capacity of bergaptol (BER) and xanthotoxol (XAN) in a nonpolar environment (benzene) was investigated against the reference standard trolox (Tx). The ability to inactivate HO radicals from the kinetic aspect was examined through hydrogen atom transfer (HAT), single-electron transfer–proton transfer (SET-PT), sequential proton loss electron transfer (SPLET) and radical adduct formation (RAF) mechanisms. The rate constants of the chemical reaction were calculated using the conventional transition state theory (TST) and Eckart method (ZCT_0). The research is based on a QM-ORSA (Quantum Mechanics–based test for Overall free-Radical Scavenging Activity) protocol. For this purpose, the Gaussian 09 software package with the M06-2X/6-311++G(d,p) theoretical model was used. It has been shown that both compounds in benzene can inactivate the HO radical via HAT and RAF mechanisms. The calculated kinetic parameters indicate that the TST method, in some positions, is not suitable for calculating reaction rate constants at room temperature. Based on relative antioxidant capacity (rT), both compounds showed better antioxidant capacity than Tx, and it should be emphasized that BER showed better activity than XAN. Based on the relative amount of products (Гi) of both compounds, it was concluded that the formation of a radical adduct in positions C-3, C-5, C-8, and C-2' is the most represented. Full article
Proceeding Paper
Green Synthesis of Symmetric Dimaleamic Acids from Dianilines and Maleic Anhydride: Behind New Bidentate Ligands for MOFs
Chem. Proc. 2021, 3(1), 92; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08379 - 14 Nov 2020
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Abstract
We herein report the synthesis and characterization of six α,β-unsaturated dicarboxylic acid ligands with different phenyl spacers, and two ligands with a biphenyl and anthraquinone spacers. All these dimaleamic acids were synthesized in 16 to 99% yields via a base-catalyzed maleimide ring opening [...] Read more.
We herein report the synthesis and characterization of six α,β-unsaturated dicarboxylic acid ligands with different phenyl spacers, and two ligands with a biphenyl and anthraquinone spacers. All these dimaleamic acids were synthesized in 16 to 99% yields via a base-catalyzed maleimide ring opening in water (ligand 2), or by a di-N-acylation from the corresponding diamines and maleic anhydride in acetic acid (ligands 4, 6, 8, 10, 12, 14 and 16). These reactions were performed using green solvents, while requiring minimal work up procedures, making them suitable alternatives to access these types of bidentate ligands quickly, which can be used to fabricate new metal-organic frameworks (MOFs). Full article
Proceeding Paper
Does Soil Organic Matter Affect the Impact of the Ionic Liquid Ethylammonium Nitrate in the Pure State and as Mixture with Lithium Salt on Basal Soil Respiration?
Chem. Proc. 2021, 3(1), 93; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08376 - 14 Nov 2020
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Abstract
Although ionic liquids (ILs) do not contaminate the atmosphere (because of their low vapour pressure), they may have toxic effects in aquatic and terrestrial environments. Therefore, before ILs can be widely used for different applications, their toxicity must be tested in different environments. [...] Read more.
Although ionic liquids (ILs) do not contaminate the atmosphere (because of their low vapour pressure), they may have toxic effects in aquatic and terrestrial environments. Therefore, before ILs can be widely used for different applications, their toxicity must be tested in different environments. The IL ethylammonium nitrate (EAN) is of interest in electrochemical applications, and research is currently underway to investigate the electrochemical activity of mixtures of this compound with inorganic salts. In this study, we investigated the impacts of different amounts of pure EAN and of mixtures of EAN and lithium salt on basal soil respiration in two soils differing in organic matter content. Full article
Proceeding Paper
Synthesis of Conjugated Polymer Based in Zn(II) Porphyrin Bearing Terminal Alkynyl Groups as Photosensitizer
Chem. Proc. 2021, 3(1), 94; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08317 - 14 Nov 2020
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Abstract
5,10,15,20-tetrakis-[4-(ethynyl)phenyl]porphyrin (TEP) was synthesized from the condensation of 4-(ethynyl)benzaldehyde and pyrrole catalyzed by boron trifluoride diethyl etherate in dichloromethane (DCM). After oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and purification, TEP was obtained in 34% yield. This porphyrin was metaled with Zn(II) acetate in DCM/methanol to produce [...] Read more.
5,10,15,20-tetrakis-[4-(ethynyl)phenyl]porphyrin (TEP) was synthesized from the condensation of 4-(ethynyl)benzaldehyde and pyrrole catalyzed by boron trifluoride diethyl etherate in dichloromethane (DCM). After oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and purification, TEP was obtained in 34% yield. This porphyrin was metaled with Zn(II) acetate in DCM/methanol to produce the complex ZnTEP in 98% yield. A homocoupling reaction of terminal alkynes of ZnTEP to diynes was used to synthesize conjugated polymer organogel (ZnTEPP). The reaction was co-catalyzed by PdCl2(PPh3)2 and CuI in tetrahydrofuran. The solvent was evaporated to obtain xerogel and the SEM images showed microporous structure. In addition, spectroscopic and photodynamic studies of ZnTEPP indicated that the porphyrin unit retains its properties as a photosensitizer. Thus, this polymer is an interesting material with potential applications in forming photoactive aseptic surfaces. Full article
Proceeding Paper
A New Fluorescent Calixarene Dimer: Synthesis, Optical Properties, and Sensory Applications
Chem. Proc. 2021, 3(1), 95; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08340 - 14 Nov 2020
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Abstract
A new fluorogenic bis-calix[4]arene-carbazole compound (3) with an enlarged intramolecular cavity able to be involved in host–guest chemistry with large organic guests was designed. Its synthesis was accomplished for the first time using a Sonogashira–Hagihara cross-coupling reaction in the final step. [...] Read more.
A new fluorogenic bis-calix[4]arene-carbazole compound (3) with an enlarged intramolecular cavity able to be involved in host–guest chemistry with large organic guests was designed. Its synthesis was accomplished for the first time using a Sonogashira–Hagihara cross-coupling reaction in the final step. The calixarene receptor was structurally characterized by FTIR and 1H/13C/2D NMR techniques and its photophysical properties evaluated. The ability of 3 to form supramolecular complexes with fullerenes (C60 and C70) was evaluated through fluorometric titration experiments. The value of the binding constants (K3:C60 = 1.39 × 105 M−1 and K3:C70= 6.88 × 104 M−1), and the free energy changes for the inclusion complexation (G3:C60 = −29.33 kJ/mol and G3:C70 = −27.60 kJ/mol), revealed a high sensitivity of the calixarene-carbazole host for both fullerenes. The host molecule was shown to be particularly selective towards fullerene C60. Full article
Proceeding Paper
DNA-Binding Properties of Cytotoxic Naphtindolizinedione-Carboxamides Acting as Type II Topoisomerase Inhibitors. A Combined In Silico and Experimental Study
Chem. Proc. 2021, 3(1), 96; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08103 - 13 Nov 2020
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Abstract
Some clinically-used anticancer drugs are DNA intercalators acting as topoisomerase (Topo) IIα poisons in tumor cells highly expressing the enzyme. Synthetic naphtindolizinedione-carboxamides, previously designed as potential antitumor agents and showing relevant cytotoxic activities in vitro, have been now evaluated for their DNA-binding and [...] Read more.
Some clinically-used anticancer drugs are DNA intercalators acting as topoisomerase (Topo) IIα poisons in tumor cells highly expressing the enzyme. Synthetic naphtindolizinedione-carboxamides, previously designed as potential antitumor agents and showing relevant cytotoxic activities in vitro, have been now evaluated for their DNA-binding and inhibition of human Topo IIα, in comparison with the drug mitoxantrone. Docking calculation of each synthetic molecule as ligand with the CGCGAATTCGCG oligonucleotide model showed a stable intercalation in the DNA cut inside the enzyme. Moreover, molecular dynamics simulation indicated the stability of each DNA complex by evaluating the H-bonds involved as a function of time. These results are correlated to spectroscopic (binding constants and melting temperature by UV–VIS analysis, circular dichroism) and biological data (cytotoxicity and inhibition of human Topo IIα decatenation assay). Full article
Proceeding Paper
Searching for New Biologically Active Compounds Derived from Isoquinoline Alkaloids
Chem. Proc. 2021, 3(1), 97; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08417 - 14 Nov 2020
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Abstract
Many isoquinoline alkaloids are biologically active compounds and successfully used as pharmaceuticals. Compounds belonging to the isoquinolines and tetrahydroisoquinolines (TIQs) can be used as anesthetics, antihypertensive drugs, antiviral agents, and vasodilators. In the presented studies, the search for new compounds and synthesis of [...] Read more.
Many isoquinoline alkaloids are biologically active compounds and successfully used as pharmaceuticals. Compounds belonging to the isoquinolines and tetrahydroisoquinolines (TIQs) can be used as anesthetics, antihypertensive drugs, antiviral agents, and vasodilators. In the presented studies, the search for new compounds and synthesis of tetrahydroisoquinoline alkaloid derivatives was undertaken. Several dihydroisoquinolines were synthesized by Bishler–Napieralski reaction from the corresponding amides. Dihydroisoquinolines were reduced with sodium borohydride to obtain racemic tetrahydroisoquinolines. Asymmetric reduction of selected 3,4-dihydroisoquinolines was attempted with borane in the presence of chiral terpene spiroboranes. Full article
Proceeding Paper
AlCl3-Catalyzed Synthesis of Zirconacyclopentadienes from Alkynes, Cp2ZrCl2 and Mg
Chem. Proc. 2021, 3(1), 98; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08363 - 14 Nov 2020
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Abstract
A new convenient preparative procedure for the preparation of zirconacyclopentadienes was developed based on the use of AlCl3-catalyzed reactions of alkyl-, aryl- and silyl-substituted alkynes with the Cp2ZrCl2–Mg reagent system, which excludes the use of both pyrophoric [...] Read more.
A new convenient preparative procedure for the preparation of zirconacyclopentadienes was developed based on the use of AlCl3-catalyzed reactions of alkyl-, aryl- and silyl-substituted alkynes with the Cp2ZrCl2–Mg reagent system, which excludes the use of both pyrophoric organometallic compounds and salts of toxic metals. In addition, the new procedure can significantly reduce the reaction time. We found that 10 mol % of AlCl3 significantly accelerates the cyclozirconation of alkyl-, aryl- and silyl-substituted alkynes giving after iodinolysis the corresponding iodine-containing homo-coupling products in a quantitative yield. Full article
Proceeding Paper
One Pot O-alkylation/Wittig Olefination of Hydroxybenzaldehydes in DMSO
Chem. Proc. 2021, 3(1), 99; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08288 - 14 Nov 2020
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Abstract
Hydroxybenzaldehydes are submitted to a one pot O-alkylation/Wittig olefination in dimethyl sulfoxide (DMSO) to give alkyl alkoxycinnamates. The reaction is carried out facilely and gives the products in high yield. Full article
Proceeding Paper
Synthesis and Structure of Novel Potentially Bioactive Amphiphilic -O-(N)-Glycosides
Chem. Proc. 2021, 3(1), 100; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08286 - 14 Nov 2020
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Abstract
Herein we present the synthesis and structural analysis of novel -O-(N)-glycosides. The biphasic reaction of NHS and acetobromo-α-d-glucose or d-galactose gives the β anomer glycoside in a straightforward manner. Further hydrazinolysis and condensation with decanal afforded the desired products. [...] Read more.
Herein we present the synthesis and structural analysis of novel -O-(N)-glycosides. The biphasic reaction of NHS and acetobromo-α-d-glucose or d-galactose gives the β anomer glycoside in a straightforward manner. Further hydrazinolysis and condensation with decanal afforded the desired products. Their complete structures, including the anomeric and E/Z double bond configurations, were determined by spectroscopic analysis. Full article
Proceeding Paper
A Comparative Theoretical and Spectroscopic Study of Aminomethylbenzoic Acid Derivatives as Potential NLO Candidates
Chem. Proc. 2021, 3(1), 102; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08099 - 13 Nov 2020
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Abstract
Three aminomethylbenzoic acid derivatives were theoretically studied at M062X/6-311++G(d,p) level in a vacuum, namely 2-ammonio-5-methylcarboxybenzene perchlorate (1), 4-(ammoniomethyl) carboxybenzene nitrate (2) and 4-(ammoniomethyl)carboxybenze perchlorate (3). The compounds’ structures were fully optimized and compared with the single-crystal X-ray [...] Read more.
Three aminomethylbenzoic acid derivatives were theoretically studied at M062X/6-311++G(d,p) level in a vacuum, namely 2-ammonio-5-methylcarboxybenzene perchlorate (1), 4-(ammoniomethyl) carboxybenzene nitrate (2) and 4-(ammoniomethyl)carboxybenze perchlorate (3). The compounds’ structures were fully optimized and compared with the single-crystal X-ray diffraction results, showing a very close agreement with the experimental structural parameters. Their IR, 1H- and 13C-NMR spectra were calculated and examined in detail. Furthermore, the molecular electrostatic potential (MEP) maps of the studied compounds were investigated and the strength of the non-covalent interactions evaluated. In addition to these results, the NLO properties of the three compounds were predicted. Full article
Proceeding Paper
Terminal Alkynes Hydroamination Catalyzed by Copper Nanoparticles
Chem. Proc. 2021, 3(1), 103; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08452 - 16 Nov 2020
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Abstract
The copper-catalyzed regioselective intermolecular hydroamination of terminal alkynes with amines was accomplished. The reaction was catalyzed by copper nanoparticles supported on montmorillonite K10 (CuNPs/MK10) and afforded the desired imines in good conversions. Then, imines were transformed into the corresponding amines after treatment with [...] Read more.
The copper-catalyzed regioselective intermolecular hydroamination of terminal alkynes with amines was accomplished. The reaction was catalyzed by copper nanoparticles supported on montmorillonite K10 (CuNPs/MK10) and afforded the desired imines in good conversions. Then, imines were transformed into the corresponding amines after treatment with NaBH3CN. The catalyst could be recovered and reutilized in several cycles. Full article
Proceeding Paper
Protective Effect of Cyclolepis genistoides Aqueous Extract against Cellular Oxidative Stress
Chem. Proc. 2021, 3(1), 104; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08344 - 14 Nov 2020
Viewed by 147
Abstract
The development of neuroprotective agents constitutes one of the most promising strategies to treat neurodegenerative disorders, such as Parkinson’s disease (PD). Oxidative stress (OS) is a major contributor to the death of dopaminergic neurons in PD. In the present work, we investigated the [...] Read more.
The development of neuroprotective agents constitutes one of the most promising strategies to treat neurodegenerative disorders, such as Parkinson’s disease (PD). Oxidative stress (OS) is a major contributor to the death of dopaminergic neurons in PD. In the present work, we investigated the effect of aqueous extracts of three Argentinian medicinal plants, Agalinis genistifolia (Cham. & Schltdl.) D’Arcy, Cyclolepis genistoides Gillies ex D. Don and Margyricarpus pinnatus (Lam.) Kuntze, on cellular models of metal-induced OS. These species have been traditionally used to treat PD-related symptoms, such as paralysis for A. genistifolia and inflammation for C. genistoides and M. pinnatus. To evaluate the potential neuroprotective activity of the aqueous extracts, we used the human neuroblastoma cell line IMR-32 exposed to ferric ammonium citrate (FAC) as an OS inducer. Whereas cells exposed to FAC exhibited increased levels of reactive oxygen species (ROS) after the treatment with A. genistifolia and M. pinnatus (50 µg/mL extract), the exposure to C. genistoides extract at 20 µg/mL showed a reduction in ROS levels. In line with this finding, we found that C. genistoides treatment decreased lipid peroxidation under the same experimental conditions (20 µg/mL). Furthermore, the induction of ROS production by manganese in IMR-32 cells and by FAC in N27 rat dopaminergic cells was attenuated by the exposure to C. genistoides extract. Our results suggest that the aqueous extract of C. genistoides has potential as a source of neuroprotective agents that can target OS, a hallmark of neuronal death in PD. Full article
Proceeding Paper
Photosynthesis-Inhibiting Activity of Methoxy-Substituted 3-Hydroxynaphthalene-2-Carboxanilides
Chem. Proc. 2021, 3(1), 105; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08295 - 14 Nov 2020
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Abstract
A set of six 3-hydroxynaphthalene-2-carboxanilides, substituted on the anilide ring by combinations of methoxy–methoxy, methoxy–fluoro and methoxy–chloro groups at different positions, was designed. All the molecules were prepared by microwave-assisted synthesis. The compounds were tested for their ability to inhibit photosynthetic electron transport [...] Read more.
A set of six 3-hydroxynaphthalene-2-carboxanilides, substituted on the anilide ring by combinations of methoxy–methoxy, methoxy–fluoro and methoxy–chloro groups at different positions, was designed. All the molecules were prepared by microwave-assisted synthesis. The compounds were tested for their ability to inhibit photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. The PET-inhibiting activity of the compounds was rather moderate. N-(3,5-Dimehoxyphenyl)-3-hydroxynaphthalene-2-carboxamide demonstrated the highest activity (IC50 = 24.5 µM) within the series. These compounds are supposed to inhibit PET in photosystem II. Full article
Proceeding Paper
Two Symmetrical Squarylium Cyanine Dyes: Synthesis, Photophysics and Antifungal Activity in Saccharomyces cerevisiae
Chem. Proc. 2021, 3(1), 106; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08423 - 14 Nov 2020
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Abstract
Two squarylium cyanine dyes were synthesized and characterized by the usual analytical techniques, including Vis-NIR absorption and emission spectroscopy. Their antifungal activity was evaluated, through the obtention of minimum inhibitory concentration (MIC) values, using yeasts of the species Saccharomyces cerevisiae as a biological [...] Read more.
Two squarylium cyanine dyes were synthesized and characterized by the usual analytical techniques, including Vis-NIR absorption and emission spectroscopy. Their antifungal activity was evaluated, through the obtention of minimum inhibitory concentration (MIC) values, using yeasts of the species Saccharomyces cerevisiae as a biological model. Full article
Proceeding Paper
Tackling Pristinamycin IIB Problems: Synthetic Studies toward Some Fluorinated Analogs
Chem. Proc. 2021, 3(1), 107; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08388 - 14 Nov 2020
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Abstract
Streptogramins are potent antibiotics against numerous highly resistant pathogens and therefore are used in last-resort human therapy. These antibiotics are formed of both A- and B-group compounds named pristinamycins that differ in their basic primary structures. Although pristinamycin IIB is among the most [...] Read more.
Streptogramins are potent antibiotics against numerous highly resistant pathogens and therefore are used in last-resort human therapy. These antibiotics are formed of both A- and B-group compounds named pristinamycins that differ in their basic primary structures. Although pristinamycin IIB is among the most interesting antibiotics in this family, it presents numerous problems related to its chemical structure, such as instability at most pH levels, weak solubility in water, and resistance by bacteria. As a response to the need for developing new antimicrobial agents, we have designed a new analog of pristinamycin IIB, based most importantly on the introduction of fluorine atoms. We conjectured indeed that the introduced modifications may solve the above-mentioned problems exhibited by pristinamycin IIB. Our multistep synthetic approach relies on few key reactions, namely a Wittig reaction, a Grubbs reaction, and dihydroxy, -difluoro API (Advanced Pharmaceutical Intermediate) synthesis Full article
Proceeding Paper
Microwave-Assisted Multicomponent Syntheses of Heterocyclic Phosphonates
Chem. Proc. 2021, 3(1), 108; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08548 - 25 Nov 2020
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Abstract
Organophosphorus compounds play an important role in the medicinal- or agricultural industry, and in the human body as well. Over the last years, heterocyclic phosphonates have received growing interest due to their potential biological activity. An efficient tool for the preparation of such [...] Read more.
Organophosphorus compounds play an important role in the medicinal- or agricultural industry, and in the human body as well. Over the last years, heterocyclic phosphonates have received growing interest due to their potential biological activity. An efficient tool for the preparation of such derivatives is their synthesis via multicomponent reactions. These transformations possess several criteria of an “ideal synthesis”, such as high atom economy, fast and simple accomplishment, energy efficiency, and environmentally friendliness. A number of heterocyclic phosphonates were prepared by us utilizing multicomponent syntheses. In this proceeding, the synthesis of the diethyl (2-amino-3-cyano-4H-chromen-4-yl)phosphonate by the condensation of salicylaldehyde, malononitrile and diethyl phosphite is briefly introduced. The reaction was optimized in respect of the catalyst type, the catalyst amount, the reaction time, and the temperature. Full article
Proceeding Paper
Selected Thermodynamic Parameters of Antioxidant Activity of Coumarin Based Heterocyclic Compounds
Chem. Proc. 2021, 3(1), 109; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08385 - 14 Nov 2020
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Abstract
Coumarin and coumarin derivatives are bioactive compounds that have an important role in medicinal chemistry, for example in the development of anti-inflammatory, anticancer and antiviral drugs. These compounds are also very powerful antioxidants that successfully scavenge free radicals and prevent or alleviate oxidative [...] Read more.
Coumarin and coumarin derivatives are bioactive compounds that have an important role in medicinal chemistry, for example in the development of anti-inflammatory, anticancer and antiviral drugs. These compounds are also very powerful antioxidants that successfully scavenge free radicals and prevent or alleviate oxidative stress. The antioxidant potential of selected heterocyclic compounds containing coumarin core was investigated theoretically, the focus of this study was on hydrogen atom transfer mechanism (HAT) and single electron transfer followed by a proton transfer mechanism (SET-PT). Using MOPAC2012 PM7, reaction enthalpies related to the cleavage of O–H, N–H and C–H bonds via selected mechanisms of free radical scavenging were studied and calculated. The effect of the position of the hydroxyl group, as well as other functional groups, on the antioxidant activity, was examined. Based on obtained results, Schiff bases, thiosemicarbazides, oxadiazoles and 4-thiazolidinones containing one or more OH– groups exhibit higher radical scavenging properties. Full article
Proceeding Paper
Electro Synthesis and Characterization of PANI and PANI/ZnO Composites Films
Chem. Proc. 2021, 3(1), 110; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08328 - 14 Nov 2020
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Abstract
The polyaniline (PANI) and ZnO doped polyaniline composite (PANI/ZnO) films were synthesized by electrochemical polymerization on transparent ITO glass substrate using cyclic voltammetry for 10th cycle by potential sweep from −200 to 900 mV vs.SCE in sulfuric acid medium with aniline monomer precursor [...] Read more.
The polyaniline (PANI) and ZnO doped polyaniline composite (PANI/ZnO) films were synthesized by electrochemical polymerization on transparent ITO glass substrate using cyclic voltammetry for 10th cycle by potential sweep from −200 to 900 mV vs.SCE in sulfuric acid medium with aniline monomer precursor and LiClO4supporting salt at room temperature. The doping effects of ZnO on PANI properties were studied; electrical properties of PANI and PANI/ZnO composite were estimated from Mott–Schottky analysis which demonstrated an n-type conductivity for all films with carrier concentrations in order of 1017and 1019 for PANI and PANI/ZnO composite respectively. The effect of the concentration of ZnO dopant in the electrolyte on the morphology and the composition of the PANI were investigated from scanning electron microscopy coupled Energy Dispersive Spectroscopy analysis (SEM+EDS). UV-VIS was investigated to study the optical characteristics of the films such as transmittance and band gap energy. The characteristics of the films were found to be depending on the concentration of ZnO particles in the electrolyte during electrochemical polymerization. Fourier transform infrared (FTIR) confirms the links and the interaction between PANI and ZnO dopant. Full article
Proceeding Paper
Molecular Docking Studies on Various Food Grade Dyes as a Potential Inhibitor of COVID-19
Chem. Proc. 2021, 3(1), 111; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08353 - 14 Nov 2020
Viewed by 145
Abstract
In December 2019, the Coronavirus disease-2019 (COVID-19) virus emerged in Wuhan, China. The first resolved COVID-19 crystal structure (main protease) has been developed and various repurposing activities are in process. In this study, a knowledge gap in relation to COVID-19, with the previously [...] Read more.
In December 2019, the Coronavirus disease-2019 (COVID-19) virus emerged in Wuhan, China. The first resolved COVID-19 crystal structure (main protease) has been developed and various repurposing activities are in process. In this study, a knowledge gap in relation to COVID-19, with the previously known fatal Coronavirus (CoV) epidemics, Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) CoVs, is covered by the investigation of sequence statistics, molecular modelling, virtual screening, docking, and sequence comparison statistics of the COVID-19 main protease. COVID-19 main protease Mpro formed a sequence similarity group with SARS CoV that was distant from MERS CoV. The identity % was 96 and 51 for COVID-19/SARS and COVID-19/MERS CoV sequence comparisons, respectively. We used molecular docking and a molecular interaction approach to identify small-molecules that bind to the isolated Viral S-protein at its host receptor region. These molecules have good solubility and pharmacodynamics properties. They also obey Lipinski’s rule, which makes them promising compounds to pursue further biochemical and cell-based assays to explore their potential for use against COVID-19. We hypothesize that the top score identified molecules that may be used to limit viral recognition of host cells and/or disrupt host-virus interactions. A ranked list of selected compounds is given that can be tested experimentally. Full article
Proceeding Paper
An Improved Stereoselective Synthesis of (1R,2S,3S,4R,5R)-4-Amino-5-(hydroxymethyl)-cyclopentane-1,2,3-triol
Chem. Proc. 2021, 3(1), 112; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08474 - 19 Nov 2020
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Abstract
Iminosugars are sugar mimetics present in plants and microorganisms that were first reported in the 1960s. [...] Full article
Proceeding Paper
Zn–Catalyzed Direct Synthesis of 3-Iodo-1,3-dienes from α-Allenols
Chem. Proc. 2021, 3(1), 113; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08091 - 13 Nov 2020
Viewed by 75
Abstract
We wish to report herein a new protocol that allows one to obtain 3-iodo-1,3-dienes through a sustainable process starting from α-allenols. In this new synthetic route, zinc (II) derivatives are used as metallic promoter, which are an inexpensive and environmentally friendly species. Full article
Proceeding Paper
Synthesis of 2-Methyl-3-nitropyridines, 2-Styryl-3-nitropyridines and Their Reactions with S-Nucleophiles
Chem. Proc. 2021, 3(1), 114; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08324 - 14 Nov 2020
Viewed by 88
Abstract
One of the most important and flexible tools for nitroarenes functionalization is nucleophilic aromatic substitution (SNAr). This reaction generally requires a number of conjugated electron-withdrawing groups and SNAr of non-activated nitro groups is rather uncommon. Most of these examples [...] Read more.
One of the most important and flexible tools for nitroarenes functionalization is nucleophilic aromatic substitution (SNAr). This reaction generally requires a number of conjugated electron-withdrawing groups and SNAr of non-activated nitro groups is rather uncommon. Most of these examples were obtained on polynitrobenzenes, but little is known about reactions of non-activated 3-nitropyridines. Here we report the synthesis of several 2-methyl-3-nitropyridines and their reactions with various aromatic aldehydes, leading to corresponding 2-styrylpyridines under mild conditions. Both 2-methyl- and 2-styryl-3-nitropyridines readily react with thiolate-anions and give substitution products in good yields. Chemoselectivity and regioselectivity is discussed, while some 2-styrylpyridines also showed remarkable fluorescent properties. Full article
Proceeding Paper
Structural Characterization by NMR Procedure of C4C1Pyrr TFSI Doped with Lithium TFSI Salt in Liquid and Gel States
Chem. Proc. 2021, 3(1), 115; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08370 - 14 Nov 2020
Viewed by 138
Abstract
Ionic liquids represent a viable option as electrolytes for electrochemical applications such as energy storage devices, due to their high ionic conductivity and wide electrochemical window. However, liquid electrolytes present important problems of safety and performance, and encapsulation in a solid matrix can [...] Read more.
Ionic liquids represent a viable option as electrolytes for electrochemical applications such as energy storage devices, due to their high ionic conductivity and wide electrochemical window. However, liquid electrolytes present important problems of safety and performance, and encapsulation in a solid matrix can be a good solution to improve it. In this work, changes in the structure of the mixtures of ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and lithium bis(trifluoromethylsulfonyl)imide against the concentration of the salt (0, 0.1, and 1.5 molal), and the effect of nanoconfinement through gelation process were studied using NMR technique. Full article
Proceeding Paper
In silico Evaluation of Antimicrobial Activity of Some Thiadiazoles Using Molecular Docking Approach
Chem. Proc. 2021, 3(1), 116; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08319 - 14 Nov 2020
Viewed by 124
Abstract
Molecular docking studies have been performed to assess the antimicrobial potential of three 1,3,4-thiadiazole derivatives containing azulene rings. The simulations were conducted on Mycobacterium tuberculosis DNA gyrase, Staphylococcus aureus DNA gyrase, and Escherichia coli DNA adenine methylase. The relationships between the structures of [...] Read more.
Molecular docking studies have been performed to assess the antimicrobial potential of three 1,3,4-thiadiazole derivatives containing azulene rings. The simulations were conducted on Mycobacterium tuberculosis DNA gyrase, Staphylococcus aureus DNA gyrase, and Escherichia coli DNA adenine methylase. The relationships between the structures of compounds and their potential antimicrobial activity were investigated. Interactions with amino acid residues from the active binding site were elucidated and the results of docking are reported in terms of docking score. Better docking scores are obtained for the investigated compounds than for the natural ligand, (4S)-2-methyl-2,4-pentanediol, in the case of the Mycobacterium tuberculosis. Two of the studied ligands present better binding affinities against Escherichia coli than the co-crystallized ones. Regarding S. aureus gyrase, the thiadiazole derivatives exhibit lower docking scores and fewer interactions than the aminobenzimidazole urea inhibitor. Our study can be useful to screen and design similar hybrid active compounds. Full article
Proceeding Paper
Intramolecular Cyclization of Alkenyl Alcohols: Towards the Synthesis of Oxacycles
Chem. Proc. 2021, 3(1), 117; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08462 - 16 Nov 2020
Viewed by 333
Abstract
The presence of tetrahydropyrans and other sized oxacycles in natural products with interesting pharmacological properties has prompted researchers to try to develop new strategies for their selective synthesis. Moreover, these methodologies enable the introduction of structural modifications in the molecule for the synthesis [...] Read more.
The presence of tetrahydropyrans and other sized oxacycles in natural products with interesting pharmacological properties has prompted researchers to try to develop new strategies for their selective synthesis. Moreover, these methodologies enable the introduction of structural modifications in the molecule for the synthesis of analogues with potential biological activity. An attractive atom economy process for the synthesis of these scaffolds is the intramolecular hydroalkoxylation of alkenes. However, this method has several drawbacks (such as the lack of generality and the presence of multiple side reactions) which have diminished its development. For many years, our research group has been devoted to developing different strategies for the regio- and stereoselective synthesis of oxygen and nitrogen heterocycles. Herein, we present our results on the effective acid catalyzed cyclization of alkenyl alcohols which bear a silyl group in their structure. As we will show, the presence of the silicon group is necessary for the cyclization to take place. Moreover, the cyclization towards tetrahydropyrans occurs with high stereoselectivity. Full article
Proceeding Paper
Investigation of Acridinedione Derivative Synthesis with Versatile Morphologies of Bi2O3 Nanoparticles
Chem. Proc. 2021, 3(1), 118; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08327 - 14 Nov 2020
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Abstract
In this study, Bi2O3 nanoparticles were successfully synthesized through a facile hydrothermal procedure. The structure of the Bi2O3 nanoparticles was analyzed by Fourier transfer infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The synthesized Bi2O [...] Read more.
In this study, Bi2O3 nanoparticles were successfully synthesized through a facile hydrothermal procedure. The structure of the Bi2O3 nanoparticles was analyzed by Fourier transfer infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The synthesized Bi2O3 nanoparticles have unique properties, such as high activity, high purity, and high surface area. Hence, we have reported the Bi2O3 nanoparticles as an efficient, cost-effective, and mild catalyst for the synthesis of acridinedione derivatives via a one-pot four-component reaction. In addition, the effect of the morphology of the Bi2O3 nanostructure was investigated on catalytic performance. Therefore, Bi2O3 nanoparticles were prepared and applied as a heterogeneous catalyst in the synthesis of acridinedione derivatives. The present approach offers several advantages, such as excellent yields within short times, green catalyst, and ease of recovery. Full article
Proceeding Paper
Electrical Conductivity and Nyquist Plot of C4C1Im BF4 at Room Temperature by Impedance Spectroscopy
Chem. Proc. 2021, 3(1), 119; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08369 - 14 Nov 2020
Viewed by 121
Abstract
Ionic liquids (ILs) represent a real alternative for electrochemical applications due to their remarkable characteristics, namely a very low vapour pressure, low flammability, high thermal stability, wide potential window and high ionic conductivity. In this work, Nyquist plot and impedance spectroscopy at room [...] Read more.
Ionic liquids (ILs) represent a real alternative for electrochemical applications due to their remarkable characteristics, namely a very low vapour pressure, low flammability, high thermal stability, wide potential window and high ionic conductivity. In this work, Nyquist plot and impedance spectroscopy at room temperature is proposed as an alternative method to obtain the ionic conductivity for ionic liquids by using an Agilent HP 4284A RLC precision meter. For this propose, the IL 1-butyl-3-methylimidazolium tetrafluoroborate (C4C1Im BF4) was selected and results were compared with the previously obtained from the conductimeter CRISON GLP31. Full article
Proceeding Paper
Synthesis of Alkenyl Sulfides Catalyzed by CuNPs/TiO2. A Theoretical-Computational Analysis
Chem. Proc. 2021, 3(1), 120; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08323 - 14 Nov 2020
Viewed by 136
Abstract
Copper nanoparticles (CuNPs) supported on TiO2 have shown to effectively catalyze the synthesis of Z-alkenyl sulfides from activated alkynes and thiol derivatives, through an anti-Markovnikov process. Activated alkynes bearing an adjacent electron-withdrawing group gave good to excellent products conversions, while [...] Read more.
Copper nanoparticles (CuNPs) supported on TiO2 have shown to effectively catalyze the synthesis of Z-alkenyl sulfides from activated alkynes and thiol derivatives, through an anti-Markovnikov process. Activated alkynes bearing an adjacent electron-withdrawing group gave good to excellent products conversions, while the unactivated alkynes did not react. In order to give an explanation to the reactivity observed from the experimental results and to know the most simple and representative structure of the catalyst, density functional theory (DFT) computational studies have been applied. Full article
Proceeding Paper
Study of ADMET Descriptors of Novel Chlorinated N-Arylcinnamamides
Chem. Proc. 2021, 3(1), 121; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08298 - 14 Dec 2020
Viewed by 322
Abstract
(2E)-3-(3,4-Dichlorophenyl)-N-arylprop-2-enanilides were designed as potential bioactive agents. Six compounds were mono- and di-chlorinated also on the anilide ring. Since the biological activities of molecules are influenced by lipophilicity, the hydro-lipophilic characteristics of these compounds were experimentally studied. In addition, [...] Read more.
(2E)-3-(3,4-Dichlorophenyl)-N-arylprop-2-enanilides were designed as potential bioactive agents. Six compounds were mono- and di-chlorinated also on the anilide ring. Since the biological activities of molecules are influenced by lipophilicity, the hydro-lipophilic characteristics of these compounds were experimentally studied. In addition, the overall ADMET (absorption, distribution, metabolism, excretion, toxicity) profiles of these molecules were studied to establish whether they comply with the Lipinski’s rule of five and thus meet the “druglikeness” requirement. All the compounds were analyzed using the reversed-phase high performance liquid chromatography method. The procedure was carried out under isocratic conditions and a C18 stationary reversed-phase column. The structure–lipophilicity relationships of the investigated compounds are discussed. Full article
Proceeding Paper
Polyphenols from Thelesperma megapotamicum and Their Antioxidant and Neuroprotective Activities
Chem. Proc. 2021, 3(1), 122; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08393 - 14 Dec 2020
Viewed by 332
Abstract
Polyphenols are attracting increasing attention in the discovery of useful agents for the treatment of neurodegenerative diseases. Thelesperma megapotamicum (Spreng.) Kuntze belongs to the family Asteraceae, which is known to have a high antioxidant capacity. The phytochemical investigation of T. megapotamicum revealed the [...] Read more.
Polyphenols are attracting increasing attention in the discovery of useful agents for the treatment of neurodegenerative diseases. Thelesperma megapotamicum (Spreng.) Kuntze belongs to the family Asteraceae, which is known to have a high antioxidant capacity. The phytochemical investigation of T. megapotamicum revealed the presence of 1′-S-isobutyroxyeugenol isobutyrate, (1), lupeol, (2), 1′-S-acetoxyeugenol isobutyrate, (3), stigmasterol, (4), β-sitosterol, (5), eriodictyol, (6), luteolin, (7), and marein, (8), as major secondary metabolites. The neuroprotective activity of this species was studied by evaluating the inhibition in vitro of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), and the antioxidant capacity of the sub-extracts and of the major metabolites isolated from them. The AChE and BChE inhibition were determined by Ellman’s method and the antioxidant activity by DPPH assay. The inhibitory activity against BChE and the antioxidant capacity of the polyphenols present in T. megapotamicum highlight this species as a promising source of active metabolites for the development of agents for the treatment of neurodegenerative diseases. Full article
Proceeding Paper
Xanthine Oxidase Inhibition by Aqueous Extract of Limonium brasiliense (Plumbaginaceae)
Chem. Proc. 2021, 3(1), 123; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08410 - 14 Dec 2020
Viewed by 541
Abstract
Limonium brasiliense (Boiss.) Kuntze (Plumbaginaceae) is a medicinal plant that is popularly used in the folk medicine. In this study, we examined xanthine oxidase (XO) inhibitory activity of the aqueous fraction of Limonium brasiliense extract and its polar bioactive constituents using the enzymatic [...] Read more.
Limonium brasiliense (Boiss.) Kuntze (Plumbaginaceae) is a medicinal plant that is popularly used in the folk medicine. In this study, we examined xanthine oxidase (XO) inhibitory activity of the aqueous fraction of Limonium brasiliense extract and its polar bioactive constituents using the enzymatic hypoxanthine (HX)–XO system in vitro. Seven active compounds isolated from the aqueous extract proved to be strong XO inhibitors. Prodelphinidin B1-3,3′-digallate (1) showed the most potent inhibitory activity with an IC50 value of 6.61 µM, comparable to allopurinol. This study provides basis for the potential use of the aqueous fraction of L. brasiliense against hyperuricemia, displaying potent XO inhibitory activity with an IC50 value of 48.3 µg/mL. This inhibitory effect is compatible with the presence of (1) in this extract. Full article
Proceeding Paper
Efficient Multicomponent Catalyst-Free Synthesis of Substituted 2-Aminopyridines
Chem. Proc. 2021, 3(1), 125; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08381 - 14 Nov 2020
Viewed by 111
Abstract
2-aminopyridines scaffolds are an important class of nitrogen heterocyclic compounds with a wide range of biological activities. Multicomponent reactions (MCRs) are useful methods for the construction of nitrogen heterocyclic compounds. In this context, syntheses of 2-aminopyridines derivatives via MCRs have attracted considerable attention [...] Read more.
2-aminopyridines scaffolds are an important class of nitrogen heterocyclic compounds with a wide range of biological activities. Multicomponent reactions (MCRs) are useful methods for the construction of nitrogen heterocyclic compounds. In this context, syntheses of 2-aminopyridines derivatives via MCRs have attracted considerable attention in recent years. We present, in this work, a rapid and efficient synthesis of 2-aminopyridine derivatives, via the catalyst-free four-component method. This protocol provides a simple and practical approach to functionalized 2-aminopyridnes from readily available substrates under solvent-free conditions. Full article
Proceeding Paper
Determination of Thermophysical Properties of the Protic Ionic Liquid EIM NO3, Pure and Doped with Lithium Nitrate Salt
Chem. Proc. 2021, 3(1), 126; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08373 - 14 Nov 2020
Viewed by 116
Abstract
In this work, viscosity, density and electrical conductivity of the ionic liquid, Ethylimidazolium Nitrate pure and doped with lithium nitrate salt were determined in order to check the properties’ improvement of the ionic liquid with the salt addition to consider these mixtures as [...] Read more.
In this work, viscosity, density and electrical conductivity of the ionic liquid, Ethylimidazolium Nitrate pure and doped with lithium nitrate salt were determined in order to check the properties’ improvement of the ionic liquid with the salt addition to consider these mixtures as potential electrolytes. Viscosity decreases exponentially as temperature increases, and increases with salt content, as expected. Density values decrease linearly as temperature increases and also increases with salt content. From electrical studies, an increase of conductivity with temperature and a decrease with salt concentration were observed. No significant differences between pure and doped sample were observed on Walden plots. Full article
Proceeding Paper
Analysis of the Relationship between the Composition of a Bronsted Acidic Task-Specific Ionic Liquid: 1-(4-Sulfonic Acid)-butyl-3-Methylimidazolium Hydrogen Sulfate ([bsmim] [HSO4]), and Its Behavior on Reactive Systems
Chem. Proc. 2021, 3(1), 127; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08375 - 14 Nov 2020
Viewed by 113
Abstract
Ionic liquids (IL) are proposed as an alternative to conventional organic solvents. Among them, there is a subgroup called task-specific ionic liquid (TSIL), in which a functional group is covalently attached to the cation or to the anion. This is allows direction towards [...] Read more.
Ionic liquids (IL) are proposed as an alternative to conventional organic solvents. Among them, there is a subgroup called task-specific ionic liquid (TSIL), in which a functional group is covalently attached to the cation or to the anion. This is allows direction towards a specific action of its chemical properties in a reactive system. In recent years, 1-(4-sulfonic acid)-3-methyl butylimidazolium [bsmim] with bisulfate counterion [HSO4] has been one of the most studied TSIL. This work aims to contribute to a better comprehension of the relationship between the structure of this TSIL and its catalytic behavior. The objective is to identify which part of the structure of the TSIL is responsible for the catalytic action observed in specific reactive systems and to understand how the addition of a functional group such as -SO3H influences the structure and therefore its behavior. 1-butyl-3-methylimidazolium [bmim] was also synthesized with the same counterion. Both ILs were tested in two reactive systems—esterification reactions and synthesis of dibenzoxanthenes. The yields obtained were compared with respect to the action of sulfuric acid. Furthermore, cyclic voltammetry was used to identify the species present in the ILs. The results indicate that TSIL shows an improved catalytic activity in both types of reactions in comparison with bmim HSO4. The relationship between the voltammetric results and the final performance allowed the interpretation of the behavior of these ILs. The IL synthesis and purification method influence on the present species and may affects the results of the reactive system. Full article
Proceeding Paper
The Structural Flexibility of Cold- and Warm-Adapted Enzymes (Endonucleases I) by Molecular Dynamics Simulation
Chem. Proc. 2021, 3(1), 128; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08387 - 14 Nov 2020
Viewed by 90
Abstract
The constraints exerted on the molecular edifices by different environmental parameters are not the same, which is translated by different adaptive strategies. Thus, for the extracellular and periplasmic enzymes of marine organisms which are directly exposed to environments in which large variations in [...] Read more.
The constraints exerted on the molecular edifices by different environmental parameters are not the same, which is translated by different adaptive strategies. Thus, for the extracellular and periplasmic enzymes of marine organisms which are directly exposed to environments in which large variations in temperature and salinity can occur, it is not an easy task to separate the adaptation of the enzyme to one of the two environmental parameters without the involvement of the other. In such a scenario, a comparative study of a marine psychrophilic and an estuarine mesophilic endonuclease I wasundertaken. The different salt optima of the enzymes were taken into consideration when the temperature-dependent enzymatic properties were characterized, but the results did not show an adaptive strategy at the molecular edifice. For that purpose, we employed multiple all-atom explicit solvent and ions molecular dynamics simulations, in conjunction with different temperatures at the nanosecond time scale to analyzethe structural flexibility of the cold adapted enzyme, endonuclease I psychrophile marine (VsEndA), and its mesophile homologous enzyme, endonuclease I mesophile estuarine (VcEndA). The Root Mean Square Fluctuation (RMSF) profiles of the two enzymes are almost similar with the most flexible residues located at the loop regions for both enzymes. We underlined a different trend against temperature for the two enzymes. The cold adapted enzyme was dominated by the lowest temperatures of T = 300 and T = 318 K, compared to its warm adapted homologous counterpart for which the highest temperature studiedwas T = 326 K as the dominantone. The lifetimes of the hydrogen bonding network of the most flexible residues of both enzymes correlate well with the RMSF of the considered enzymes. Full article
Proceeding Paper
Synthesis of Functionalized Thiopyrano [2,3-b]quinolines via Cascade Reactions Catalyzed by Magnetic Arginine/Alginate Biocomposite
Chem. Proc. 2021, 3(1), 129; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08413 - 14 Nov 2020
Viewed by 110
Abstract
An effective synthesis of functionalized thiopyrano [2,3-b]quinolines has been described via cascade reactions using super paramagnetic iron oxide nanoparticles (SPIONs) coated with l-arginine (Arg) grafted alginate (Alg), called Fe3O4@[email protected]@Arg. The reaction was performed between commercially available CH [...] Read more.
An effective synthesis of functionalized thiopyrano [2,3-b]quinolines has been described via cascade reactions using super paramagnetic iron oxide nanoparticles (SPIONs) coated with l-arginine (Arg) grafted alginate (Alg), called Fe3O4@[email protected]@Arg. The reaction was performed between commercially available CH acid compounds such as dimedone or malononitrile, and 2-mercapto-quinoline-3-carbaldehydes under green conditions. This efficient method provides a new route for the formation of functionalized three or four fused rings. Full article
Proceeding Paper
A Simple and Sustainable Synthetic Lab-Protocol for Obtaining Racemic Dominicalure-Aggregation Pheromone of the Grain Beetle Rhyzopertha dominica F. (Coleoptera, Bostrichidae)
Chem. Proc. 2021, 3(1), 130; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08284 - 14 Nov 2020
Viewed by 122
Abstract
The pheromones constitute a decisive component in the strategies for the conservation of stored foods. In Ecuador, several studies are developing, under eco sustainable conditions, on synthetic pheromones and their applicability in the control of species Rhyzopertha dominica, which causes severe damage [...] Read more.
The pheromones constitute a decisive component in the strategies for the conservation of stored foods. In Ecuador, several studies are developing, under eco sustainable conditions, on synthetic pheromones and their applicability in the control of species Rhyzopertha dominica, which causes severe damage in stored grains. Previously reported information details the use of expensive reagents for carrying out the synthesis of the aggregation pheromone of this species. Using propionic and isobutiric aldehydes as starting substrates by means of aldolic condensation, selective oxidation with Ag2O-methanol of monoenic aldehydes, treatment with SOCl2, and esterification with 2-pentanol, the respective components of the racemic aggregation pheromone of this species were synthesized. Full article
Proceeding Paper
Thermal Behaviour of Ionogels Based on Ionic Liquid Lithium Salt Mixtures
Chem. Proc. 2021, 3(1), 131; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08371 - 14 Nov 2020
Viewed by 111
Abstract
The thermal behavior of the mixtures of two protic ionic liquids (ethylammonium nitrate (EAN) and ethylimidazolium nitrate ([EIm][NO3])) with lithium nitrate salt (LiNO3), and one aprotic ionic liquid (butyl methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMpyrr][TFSI)) with lithium bis(trifluoromethylsulfonyl)imide salt (LiTFSI), at different [...] Read more.
The thermal behavior of the mixtures of two protic ionic liquids (ethylammonium nitrate (EAN) and ethylimidazolium nitrate ([EIm][NO3])) with lithium nitrate salt (LiNO3), and one aprotic ionic liquid (butyl methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMpyrr][TFSI)) with lithium bis(trifluoromethylsulfonyl)imide salt (LiTFSI), at different concentrations, was studied in this work using a Differential Scanning Calorimeter (DSC-Q2000-TA Instruments). Comparisons with the thermal behavior of silica-based ionogels of these mixtures were also performed. Full article
Proceeding Paper
Synthesis of Amidines and Its Application to Pyrimidouracil Synthesis
Chem. Proc. 2021, 3(1), 132; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08503 - 20 Nov 2020
Viewed by 308
Abstract
An efficient and sustainable copper-catalyzed protocol has been developed for the preparation of amidines via nucleophilic addition of amines into nitriles. The reaction proceeded smoothly at 100 °C in the presence of CuCl, Cs2CO3, and 2,2/-bipyridine under [...] Read more.
An efficient and sustainable copper-catalyzed protocol has been developed for the preparation of amidines via nucleophilic addition of amines into nitriles. The reaction proceeded smoothly at 100 °C in the presence of CuCl, Cs2CO3, and 2,2/-bipyridine under oxygen (O2) atmosphere in 2,2,2-trifluoroethanol (TFE) solvent. Moreover, a straightforward synthetic method for the synthesis of substituted pyrimidouracils via PhI(OAc)2-mediated oxidative coupling of N-uracil amidines and methylarenes has been developed. The starting materials N-uracil amidines were synthesized from 6-chlorouracil and amidines via nucleophilic substitution reactions. Full article
Proceeding Paper
Synthesis of Porphyrins with ABAB Symmetry from Dipyrromethanes as Potential Phototherapeutic Agents
Chem. Proc. 2021, 3(1), 133; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08305 - 14 Nov 2020
Viewed by 149
Abstract
Asymmetrically meso-substituted porphyrins were synthesized with ABAB symmetry patterns. The approach required the formation of dipyrromethanes, which were obtained from the condensation of an aldehyde (pentafluorobenzaldehyde, 4-nitrobenzaldehyde or N,N-diphenylaminobenzaldehyde) with a large excess of pyrrole (1:47 aldehyde/pyrrole mol ratio), [...] Read more.
Asymmetrically meso-substituted porphyrins were synthesized with ABAB symmetry patterns. The approach required the formation of dipyrromethanes, which were obtained from the condensation of an aldehyde (pentafluorobenzaldehyde, 4-nitrobenzaldehyde or N,N-diphenylaminobenzaldehyde) with a large excess of pyrrole (1:47 aldehyde/pyrrole mol ratio), catalyzed by trifluoroacetic acid in 70–94% yields. Then, acid-catalyzed condensation of these dipyrromethanes with an aldehyde (N,N-dimethylaminobenzaldehyde, 4-carboxymethyl benzaldehyde or N-ethyl-3-carbazolecarbaldehyde) (1:1 mol ratio) in dichloromethane, followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone affords the diseased porphyrins in 10–42% yields. These ABAB-porphyrins are interesting starting materials to obtain photoactive molecular structures as potential phototherapeutic agents. Full article
Proceeding Paper
Study of a New Hydrazone System with Ion Complexation Capacity Suitable for Selective Detection
Chem. Proc. 2021, 3(1), 134; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08392 - 14 Nov 2020
Viewed by 123
Abstract
The design and synthesis of chemosensors that allows the selectively detection of heavy metal cations by complexation, is an area of growing interest. The hydrazone functional group has been widely used in supramolecular chemistry due to its complexing capacity, its conjugated electrons, and [...] Read more.
The design and synthesis of chemosensors that allows the selectively detection of heavy metal cations by complexation, is an area of growing interest. The hydrazone functional group has been widely used in supramolecular chemistry due to its complexing capacity, its conjugated electrons, and its simple methods of synthesis. In this way, a nitrogen system derived from the condensation of vanillin (aromatic aldehyde) and 2-hydrazinobenzothiazole to give the corresponding hydrazone for the detection of Cu2+ was developed. Spectroscopic determinations demonstrate whether the complexing took place. The hidrazone showed a response in UV–vis spectroscopy and a color shift is observed with the naked eye. In addition, theoretical analysis based on the Density Functional Theory (DFT) was realized to understand the chemical changes that the ligand suffers in the complexation process with the Cu2+ ion through the study of the structural, electronics, and optical properties. Full article
Proceeding Paper
One-Pot Synthesis of N-Alkylated 2-Pyridone Derivatives under Microwave Irradiation
Chem. Proc. 2021, 3(1), 135; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08412 - 14 Nov 2020
Viewed by 133
Abstract
The specific synthesis of N-alkylated pyridone has attracted considerable attention due to the presence of these units in a wide range of components, both in natural products and in many active pharmaceuticals. Generally, the synthesis of N-alkyl-2-pyridones is feasible by the [...] Read more.
The specific synthesis of N-alkylated pyridone has attracted considerable attention due to the presence of these units in a wide range of components, both in natural products and in many active pharmaceuticals. Generally, the synthesis of N-alkyl-2-pyridones is feasible by the alkylation of 2-pyridones. In this case, selectively witching the reaction is required to induce N- or O-alkylation. In this communication, we present our results of the synthesis of different N-substituted 2-pyridone using multicomponent reactions (MCRs) methods under microwave radiation conditions. Full article
Proceeding Paper
Cumulative Cytotoxicity Assay of the Aqueous and Ethanolic Extracts of the Selected Medicinal Plants Using Crown Gall Tumor Disc Bioassay
Chem. Proc. 2021, 3(1), 136; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08297 - 14 Nov 2020
Viewed by 244
Abstract
The present study was carried out to test an in vivo crown gall tumor disc bioassay using potato discs of the aqueous and ethanolic extracts of Annona reticulata with Allium sativum, Allium fistolisum, Brassica oleraceae, and then correlate the cytotoxicity [...] Read more.
The present study was carried out to test an in vivo crown gall tumor disc bioassay using potato discs of the aqueous and ethanolic extracts of Annona reticulata with Allium sativum, Allium fistolisum, Brassica oleraceae, and then correlate the cytotoxicity results with the known pharmacological activities of the plants. Cytotoxicity was evaluated according to the crown gall tumor disc bioassay, a highly specific, quantitative method that requires only a short period of time to return results of crown gall tumor formation. The results shows the cumulative activity of the extracts of Annona reticulate extract with Allium sativum, Allium fistolisum and Brassica oleraceae extracts and shown they were potent against the bioassay as compared to their being used alone with combined extracts. The results indicated that their bioactive components have considerable pharmacological effects. Thus, the results supported the uses of these plant species in traditional medicine. Full article
Proceeding Paper
Evaluation of Phytochemical & Antimitotic Potential of Annona Reticulata Extracts by Onion Root Model
Chem. Proc. 2021, 3(1), 137; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08296 - 14 Nov 2020
Viewed by 278
Abstract
This study investigated photochemical investigation and extraction methods with polar and non-polar solvent which could be used to compare and see the effectiveness of each on the chromosomes. The FTIR spectrum shows the presence of acetogenins in the extracts. Cytotoxic effects were studied [...] Read more.
This study investigated photochemical investigation and extraction methods with polar and non-polar solvent which could be used to compare and see the effectiveness of each on the chromosomes. The FTIR spectrum shows the presence of acetogenins in the extracts. Cytotoxic effects were studied using Allium cepa root tip cells. Eight onion bulbs were subjected to the treatment groups which were made using water, methanol, Ethyl acetate, acetone and hexane extracts of A. reticulata. Three different concentrations from each extraction solvent were used. The A. cepa root tip cells were subjected for 24 h to three different leaf extractions after left to grow in water. Concentrations of 0.1, 1, 10 and 50 mg/L were used. All studied concentrations of A. reticulata methanol extract showed significant (p < 0.05) drop in the mean mitotic index when compared with control Overall decrease in MI was contributed to by all the stages of mitosis. Full article
Proceeding Paper
In Silico Identification of Protein Targets Associated to the Insecticide Activity of Eugenol Derivatives
Chem. Proc. 2021, 3(1), 138; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08333 - 14 Nov 2020
Viewed by 273
Abstract
The control of insect pests and the need for increased food production due to the world population growth, together with environmental issues associated with synthetic pesticides, has stimulated the development of new and “greener” alternatives, based on natural compounds. Eugenol is a natural [...] Read more.
The control of insect pests and the need for increased food production due to the world population growth, together with environmental issues associated with synthetic pesticides, has stimulated the development of new and “greener” alternatives, based on natural compounds. Eugenol is a natural compound that is the major component of clove oil. It has demonstrated antimicrobial and antioxidant activity, being also a powerful insecticide. Recently, new eugenol derivatives have been developed, with some molecules displaying increased insecticide activity. One of the difficulties associated with the rational development of new eugenol derivatives with enhanced insecticidal activity lies in the lack of knowledge of the specific protein target responsible for its activity and to the binding conformation of these molecules. Here, we report the application of an integrated molecular modeling—inverted virtual screening protocol of a collection of eugenol derivatives with confirmed insecticide activity against a molecular library of protein targets typically associated with the insecticide activity of natural compounds. The protocol included six different scoring functions from popular docking software alternatives. The results consistently show a marked preference for interaction of the eugenol derivatives with the odorant binding proteins (OBPs) in insect species. Interestingly, OBPs have been regarded as promising targets in the insect periphery nerve system for environmental-friendly approaches in insect pest management. The present results provide clues for the rational development of new eugenol derivatives as bioinsecticides targeting OBPs. Full article
Proceeding Paper
Preliminary Evaluation of Pullulan Nanoparticles Loaded with Valsartan
Chem. Proc. 2021, 3(1), 139; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08428 - 14 Nov 2020
Viewed by 285
Abstract
The objective of this paper is to develop polymeric nanoparticles loaded with a cardiovascular drug (an angiotensin II receptor blocker, valsartan). Polymeric nanoparticles were prepared via the nanoprecipitation method using pullulan acetate as biodegradable polymeric matrix and Pluronic F127 as a stabilizer. Pullulan [...] Read more.
The objective of this paper is to develop polymeric nanoparticles loaded with a cardiovascular drug (an angiotensin II receptor blocker, valsartan). Polymeric nanoparticles were prepared via the nanoprecipitation method using pullulan acetate as biodegradable polymeric matrix and Pluronic F127 as a stabilizer. Pullulan acetate was obtained through the chemical modification of pullulan (produced through a fermentation process using the Aureobasidium pullulans strain) with dimethylformamide, pyridine and acetic anhydride. The obtained nanoparticles were characterized in terms of entrapment efficiency, size, and polydispersity index using spectrophotometric and dynamic light scattering techniques. The valsartan-loaded nanoparticles showed a good entrapment efficiency of valsartan, nanometric sizes (lower than 200 nm), and a narrow dispersity (polydispersity index below 0.2). This research revealed that pullulan and pullulan derivatives show great potential for the production of nanoparticles, with potential application in the delivery of cardiovascular agents. Full article
Proceeding Paper
Intracellular Uptake Study of Polymeric Nanoparticles Loaded with Cardiovascular Drugs Using Confocal Laser Scanning Microscopy
Chem. Proc. 2021, 3(1), 140; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08427 - 14 Nov 2020
Viewed by 271
Abstract
Confocal laser scanning microscopy (CSLM) is a powerful microscopic tool that gives valuable morphological and functional information within cells and tissues. CLSM is non-invasive, with high-contrast scanning, a simple and fast sample preparation procedure as well as easy operation. This paper aimed to [...] Read more.
Confocal laser scanning microscopy (CSLM) is a powerful microscopic tool that gives valuable morphological and functional information within cells and tissues. CLSM is non-invasive, with high-contrast scanning, a simple and fast sample preparation procedure as well as easy operation. This paper aimed to study the intracellular uptake of polymeric nanoparticles loaded with cardiovascular drugs using confocal laser scanning microscopy. Polymeric nanoparticles were prepared via nanoprecipitation method using poly(lactide-co-glycolide) (PLGA) as a biodegradable polymeric matrix and Pluronic F127 as a stabilizer. A mixture of two cardiovascular drugs—valsartan (an angiotensin II receptor antagonist drug) and amlodipine besylate (a calcium channel blocker)—was loaded in polymeric nanoparticles. The prepared polymeric nanoparticles had sizes lower than 300 nm and narrow dispersity. The cellular uptake of polymeric nanoparticles was investigated by incubating adherent mouse embryo fibroblasts (NIH 3T3) with a suspension of nanoparticles (stained previously with phthalocyanine) at three different time points. Targeted cell compartments were labeled with two fluorophores: Rhodamine B (membrane stain) and Hoechst (nucleic acid stain). Live cell imaging was performed using a confocal microscope Zeiss LSM710 with Zeiss PALM microdissection system. The intracellular uptake of polymeric nanoparticles was revealed by confocal laser scanning microscopy for each incubation time. The results suggest a possible mechanism of endocytosis and clearly a vesicular-based accumulation of the nanoparticles in the cytoplasmatic compartments. Full article
Proceeding Paper
Uncommon Coordination Modes of a Potential Heptadentate Aminophenol Donor
Chem. Proc. 2021, 3(1), 141; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08293 - 14 Nov 2020
Viewed by 127
Abstract
This work describes the synthesis, characterization and reactivity towards HoIII of a potential heptadentate N4O3 aminophenol donor. The crystal structure of the [Ho(1,1,4-H3L)(1,1,4-H6L)] complex (1,1,4-H6L = 6,6′-(2-(5-bromo-2-hydroxy -3-nitrobenzyl)-2,5,8,11-tetraazadodecane-1,12-diyl)bis(4-bromo-2-nitrophenol)) shows that the holmium atom [...] Read more.
This work describes the synthesis, characterization and reactivity towards HoIII of a potential heptadentate N4O3 aminophenol donor. The crystal structure of the [Ho(1,1,4-H3L)(1,1,4-H6L)] complex (1,1,4-H6L = 6,6′-(2-(5-bromo-2-hydroxy -3-nitrobenzyl)-2,5,8,11-tetraazadodecane-1,12-diyl)bis(4-bromo-2-nitrophenol)) shows that the holmium atom binds two aminophenol ligands, one acting as trianionic hexadentate, and the other one as neutral monodentate. As far as we know, both coordination modes of the aminophenol are hitherto unknown for this kind of scarcely reported ligand. This leads to coordination number 7 for the HoIII ion, which is in a capped trigonal prism environment. Full article
Proceeding Paper
Effect on Cycloaddition Reactions of Aqueous Micellar Systems Formed by Amphiphilic Imidazolium Ionic Liquids
Chem. Proc. 2021, 3(1), 142; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08338 - 14 Nov 2020
Viewed by 211
Abstract
The micellar effect on Diels–Alder (DA) reaction was analyzed taking advantage of the property presented by ionic liquids (ILs) based on 1-alkyl-3-methylimidazolium cations by having amphiphilic character when the alkyl group is a long hydrocarbon chain-12 carbon atoms [C12mim]. These ILs [...] Read more.
The micellar effect on Diels–Alder (DA) reaction was analyzed taking advantage of the property presented by ionic liquids (ILs) based on 1-alkyl-3-methylimidazolium cations by having amphiphilic character when the alkyl group is a long hydrocarbon chain-12 carbon atoms [C12mim]. These ILs can act as surfactants forming micelles in aqueous solution. The reactive system studied consists of nitrofuran and isoprene which allows obtaining benzofuran through green synthetic strategies. These “new microheterogeneous systems” would allow a better solubilization of non-polar substrates and to adopt reaction conditions softer than the traditional thermal. Full article
Proceeding Paper
Studies on mcl-Polyhydroxyalkanoates Using Different Carbon Sources for New Biomedical Materials
Chem. Proc. 2021, 3(1), 143; https://0-doi-org.brum.beds.ac.uk/10.3390/ecsoc-24-08429 - 14 Nov 2020
Viewed by 35
Abstract
Polyhydroxyalkanoates (PHAs) are microbial homo- and copolymers of [R]-β-hydroxyalkanoic acids, produced by a wide variety of bacteria as an intracellular carbon and energy reserve. To obtain mcl-PHAs of microbial origin, we used a Pseudomonas spp. strain (from the National Institute for Chemical-Pharmaceutical [...] Read more.
Polyhydroxyalkanoates (PHAs) are microbial homo- and copolymers of [R]-β-hydroxyalkanoic acids, produced by a wide variety of bacteria as an intracellular carbon and energy reserve. To obtain mcl-PHAs of microbial origin, we used a Pseudomonas spp. strain (from the National Institute for Chemical-Pharmaceutical Research and Development (ICCF) culture collection of micro-organisms), by varying the carbon sources and the precursors. In this work, assays were performed with fermentation media seeded with inoculum cultures of strain Pseudomonas putida in a proportion of 10%. The influence on strain development and mcl-PHA production of carbon sources consisting in C6, C7, C8 and C9 fatty acids (as polymers precursors) was analyzed. Due to their properties, similar to conventional plastics and their biodegradability, PHAs are suitable for many applications and for biomedical materials useful in surgical sutures, tissue engineering and drugs carriers, leading us to deepen the study of obtaining micro/nanofibers by the electrospinning method. Full article
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