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Molbank, Volume 2021, Issue 2 (June 2021) – 41 articles

Cover Story (view full-size image): Dibromo derivatives of benzofused chalcogen–nitrogen heterocycles are important precursors in the synthesis of various photovoltaic materials. 4,7-Dibromobenzo[d][1,2,3]thiadiazole is an isomer and the closest analogue of the well-known 4,7-dibromobenzo[c][1,2,5]thiadiazole, but thus far, it has yet to be studied. We studied the nucleophilic substitution of this compound with morpholine and showed that the bromine atom in the 4-position of 4,7-dibromobenzo[d][1,2,3]thiadiazole is selectively substituted. The structure of the synthesized 4-(7-bromobenzo[d][1,2,3]thiadiazol-4-yl)morpholine was fully characterized by elemental analysis, high-resolution mass spectrometry, 1H, 13C NMR and IR spectroscopy, mass spectrometry and X-ray structural analysis. View this paper.
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Short Note
5-((8-Hydroxyquinolin-5-yl)diazenyl)-3-methyl-1H-pyrazole-4-carboxylic Acid
Molbank 2021, 2021(2), M1238; https://0-doi-org.brum.beds.ac.uk/10.3390/M1238 - 16 Jun 2021
Viewed by 503
Abstract
A new azo compound was prepared via the azo coupling reaction between 4-(ethoxycarbonyl)-3-methyl-1H-pyrazole-5-diazonium chloride and 8-hydroxyquinoline (oxine). The ester functional group of the obtained compound was hydrolyzed and thus a new chemical structure with a carboxylic functional group resulted. The structures [...] Read more.
A new azo compound was prepared via the azo coupling reaction between 4-(ethoxycarbonyl)-3-methyl-1H-pyrazole-5-diazonium chloride and 8-hydroxyquinoline (oxine). The ester functional group of the obtained compound was hydrolyzed and thus a new chemical structure with a carboxylic functional group resulted. The structures of the new compounds were fully characterized by: UV–Vis, FT-IR, 1D and 2D NMR spectroscopy, and HRMS spectrometry. Full article
(This article belongs to the Section Organic Synthesis)
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Scheme 1

Short Note
4-Amino-2-(p-tolyl)-7H-chromeno[5,6-d]oxazol-7-one
Molbank 2021, 2021(2), M1237; https://0-doi-org.brum.beds.ac.uk/10.3390/M1237 - 15 Jun 2021
Viewed by 493
Abstract
The new 4-amino-2-(p-tolyl)-7H-chromeno[5,6-d]oxazol-7-one was successfully prepared through the Au/TiO2-catalyzed NaBH4 activation and chemoselective reduction of the new 4-nitro-2-(p-tolyl)-7H-chromeno[5,6-d]oxazol-7-one. The latter was synthesized by the one-pot tandem reactions of [...] Read more.
The new 4-amino-2-(p-tolyl)-7H-chromeno[5,6-d]oxazol-7-one was successfully prepared through the Au/TiO2-catalyzed NaBH4 activation and chemoselective reduction of the new 4-nitro-2-(p-tolyl)-7H-chromeno[5,6-d]oxazol-7-one. The latter was synthesized by the one-pot tandem reactions of 6-hydroxy-5,7-dinitrocoumarin with p-tolylmethanol under Au/TiO2 catalysis. The dinitrocoumarin was obtained by the nitration of 6-hydroxycoumarin with cerium ammonium nitrate (CAN). The structure of the synthesized compounds was confirmed by FT-IR, HR-MS, 1H-NMR and 13C-NMR analysis. Preliminary biological tests show low anti-lipid peroxidation activity for the title compound. Full article
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Short Note
(E)-2-(2-Oxo-4-phenylbut-3-en-1-yl)benzo[d]thiazole-3(2H)-carboxylates
Molbank 2021, 2021(2), M1236; https://0-doi-org.brum.beds.ac.uk/10.3390/M1236 - 13 Jun 2021
Viewed by 874
Abstract
An convenient one-pot approach for the synthesis of new (E)-2-(2-oxo-4-phenylbut-3-en-1-yl)benzo[d]thiazole-3(2H)-carboxylates is demonstrated. The method is based on a three-component reaction of benzylideneacetone with electrophilic N-alkoxycarbonylbenzothiazolium species formed in situ. The newly synthesized compounds were fully [...] Read more.
An convenient one-pot approach for the synthesis of new (E)-2-(2-oxo-4-phenylbut-3-en-1-yl)benzo[d]thiazole-3(2H)-carboxylates is demonstrated. The method is based on a three-component reaction of benzylideneacetone with electrophilic N-alkoxycarbonylbenzothiazolium species formed in situ. The newly synthesized compounds were fully characterized by 1D 1H, 13C- NMR, IR and MS. Full article
(This article belongs to the Section Organic Synthesis)
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Article
Ag(I) Complexes of Imine Derivatives of Unexpected 2-Thiophenemethylamine Homo-Coupling and Bis-(E)-N-(furan-2-ylmethyl)-1-(quinolin-2-yl)methanimine
Molbank 2021, 2021(2), M1235; https://0-doi-org.brum.beds.ac.uk/10.3390/M1235 - 12 Jun 2021
Cited by 1 | Viewed by 667
Abstract
Imines are fundamental organic compounds used as synthetic intermediates and as ligands in coordination chemistry. They are also found to be important pharmacophores in various bioactive compounds. In this report, two Schiff bases were prepared using the traditional condensation of 4-pyridinecarboxaldehyde with 2-thiophenemethylamine [...] Read more.
Imines are fundamental organic compounds used as synthetic intermediates and as ligands in coordination chemistry. They are also found to be important pharmacophores in various bioactive compounds. In this report, two Schiff bases were prepared using the traditional condensation of 4-pyridinecarboxaldehyde with 2-thiophenemethylamine and 2-quinolinecarboxaldehyde with furfurylamine to form (E)-1-(pyridin-4-yl)-N-(thiophen-2-ylmethyl)methanimine (L1) and (E)-N-(furan-2-ylmethyl)-1-(quinolin-2-yl)methanimine (L2) respectively. L1 and L2 were complexed with silver perchlorate in 2:1 [M:L] stoichiometry to obtain complexes 1 and 2, respectively. The crystal structures of 1 and 2 were unequivocally determined by single-crystal X-ray diffraction analysis. The resulting structures revealed 2 to be a four-coordinate as expected. In contrast, an unexpected chemoselective hydrolytic cleavage of one mole of the (CH=N) imine ligands occurred in complex 2 and, further, the amines (thiophenemethylamine) homo-coupled to form a new imine ligand derivative in situ (L1a) before coordinating to the Ag(I) center along with L1. This observation described an alternative synthetic route to be explored to synthesize a diverse range of imine derivatives, which involves the Ag(I)-promoted homo-coupling of amines. Herein, the crystal structures of Ag(I) complexes of pyridinyl [Ag(L1)(L1a)]ClO4 (1) and quinolinyl [Ag(L2)2]ClO4 (2) Schiff bases are presented. Full article
(This article belongs to the Section Organic Synthesis)
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Communication
Bioactive Antidiabetic Flavonoids from the Stem Bark of Cordia dichotoma Forst.: Identification, Docking and ADMET Studies
Molbank 2021, 2021(2), M1234; https://0-doi-org.brum.beds.ac.uk/10.3390/M1234 - 11 Jun 2021
Cited by 1 | Viewed by 687
Abstract
Cordia dichotoma Forst. (F. Boraginaceae) has been traditionally used for the management of a variety of human ailments. In our earlier work, the antidiabetic activity of methanolic bark extract of C. dichotoma (MECD) has been reported. In this paper, two flavonoid molecules were [...] Read more.
Cordia dichotoma Forst. (F. Boraginaceae) has been traditionally used for the management of a variety of human ailments. In our earlier work, the antidiabetic activity of methanolic bark extract of C. dichotoma (MECD) has been reported. In this paper, two flavonoid molecules were isolated (by column chromatography) and identified (by IR, NMR and mass spectroscopy/spectrometry) from the MECD with an aim to investigate their antidiabetic effectiveness. Molecular docking and ADMET studies were carried out using AutoDock Vina software and Swiss ADME online tool, respectively. The isolated flavonoids were identified as 3,5,7,3′,4′-tetrahydroxy-4-methoxyflavone-3-O-l-rhamnopyranoside and 5,7,3′-trihydroxy-4-methoxyflavone-7-O-l-rhamnopyranoside (quercitrin). Docking and ADMET studies revealed the promising binding affinity of flavonoid molecules for human lysosomal α-glucosidase and human pancreatic α-amylase with acceptable ADMET properties. Based on computational studies, our study reports the antidiabetic potential of the isolated flavonoids with predictive pharmacokinetics profile. Full article
(This article belongs to the Special Issue Synthesis of Flavonoids or Other Nature-Inspired Small Molecules)
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(E)-4-Oxo-3,4-dihydroquinazoline-2-carbaldehyde Oxime
Molbank 2021, 2021(2), M1233; https://0-doi-org.brum.beds.ac.uk/10.3390/M1233 - 11 Jun 2021
Viewed by 578
Abstract
Reaction of 4-oxo-3,4-dihydroquinazoline-2-carbaldehyde with hydroxylamine hydrochloride (1.1 equiv) in the presence of K2CO3 (1 equiv) gave (E)-4-oxo-3,4-dihydroquinazoline-2-carbaldehyde oxime (8) in 58% yield. The compound was fully characterized and the conformation of the oxime was supported by single crystal x-ray diffractometry. Full article
(This article belongs to the Special Issue Heterocycle Reactions)
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Short Note
Kokosanolide D: A New Tetranortriterpenoid from Fruit Peels of Lansium domesticum Corr. cv Kokossan
Molbank 2021, 2021(2), M1232; https://0-doi-org.brum.beds.ac.uk/10.3390/M1232 - 10 Jun 2021
Viewed by 694
Abstract
A novel tetranortriterpenoid named kokosanolide D has been isolated from fruit peels of Lansium domesticum. The structure of kokosanolide D was elucidated primarily on the basis of spectroscopic data including infrared, 1D and 2D-NMR, as well as high resolution mass spectroscopy analysis [...] Read more.
A novel tetranortriterpenoid named kokosanolide D has been isolated from fruit peels of Lansium domesticum. The structure of kokosanolide D was elucidated primarily on the basis of spectroscopic data including infrared, 1D and 2D-NMR, as well as high resolution mass spectroscopy analysis and comparison with related compounds previously reported. Full article
(This article belongs to the Special Issue Synthesis of Flavonoids or Other Nature-Inspired Small Molecules)
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Short Note
(R,S)-2-{[4-(4-Methoxyphenyl)-5-phenyl-4H-1,2,4-triazol-3-yl] thio}-1-phenyl-1-ethanol
Molbank 2021, 2021(2), M1231; https://0-doi-org.brum.beds.ac.uk/10.3390/M1231 - 08 Jun 2021
Viewed by 583
Abstract
4-(4-Methoxyphenyl)-5-phenyl--4H-1,2,4-triazole-3-thiol (4) was alkylated to 2-{[4-(-4-methoxyphenyl)-5-phenyl-4H-1,2,4-triazol-3-yl]thio}-1-phenylethan-1-one (5) in alkaline conditions using 2-bromo-1-phenylethanone. The alkylated compound (5) was reduced at the carbonyl group to the corresponding racemic secondary alcohol with an asymmetric carbon, ( [...] Read more.
4-(4-Methoxyphenyl)-5-phenyl--4H-1,2,4-triazole-3-thiol (4) was alkylated to 2-{[4-(-4-methoxyphenyl)-5-phenyl-4H-1,2,4-triazol-3-yl]thio}-1-phenylethan-1-one (5) in alkaline conditions using 2-bromo-1-phenylethanone. The alkylated compound (5) was reduced at the carbonyl group to the corresponding racemic secondary alcohol with an asymmetric carbon, (R,S)-2-{[4-(4-methoxyphenyl)-5-phenyl-4H-1,2,4-triazol-3-yl]thio}-1-phenyl-1-ethanol (6). Both synthesized compounds, ketone (5) and secondary alcohol (6), are new and have not been reported yet in the literature. All the synthesized compounds were characterized by IR, 1D and 2D NMR 1H-1H, 1H-13C and 1H-15N-NMR spectroscopy and by elemental analysis. Full article
(This article belongs to the Section Organic Synthesis)
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Short Note
Crystal Structure of 9-Dibenzylsulfide-7,8-dicarba-nido-undecaborane 9-Bn2S-7,8-C2B9H11
Molbank 2021, 2021(2), M1230; https://0-doi-org.brum.beds.ac.uk/10.3390/M1230 - 07 Jun 2021
Viewed by 669
Abstract
The crystal structure of 9-dibenzylsulfide-7,8-dicarba-nido-undecaborane 9-Bn2S-7,8-C2B9H11 was determined by a single-crystal X-ray diffraction. One of the benzyl groups is located above the open face of the carborane cage with a short H···H distance (2.29 [...] Read more.
The crystal structure of 9-dibenzylsulfide-7,8-dicarba-nido-undecaborane 9-Bn2S-7,8-C2B9H11 was determined by a single-crystal X-ray diffraction. One of the benzyl groups is located above the open face of the carborane cage with a short H···H distance (2.29 and 2.71 Å for two symmetrically independent molecules) between the BHB-bridging hydrogen atom of the carborane fragment and the ortho-CH group of the aromatic ring. Topological analysis has revealed the existence of a critical bond point with a calculated energy of −0.8 kcal/mol in accordance with an X-ray diffraction molecular geometry. The crystal packing analysis revealed that this benzyl group is also involved in π-stacking interactions, while another benzyl group participates in numerous weak H···π, H···H and van der Waals interactions. Full article
(This article belongs to the Section Structure Determination)
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Short Note
7-Bromo-[1,2,5]selenadiazolo[3,4-d]pyridazin-4(5H)-one
Molbank 2021, 2021(2), M1229; https://0-doi-org.brum.beds.ac.uk/10.3390/M1229 - 05 Jun 2021
Viewed by 627
Abstract
New heterocyclic systems containing 1,2,5-chalcogenadiazoles are of great interest for the creation of organic photovoltaic materials and biologically active compounds. In this communication, 3,6-dibromopyridazine-4,5-diamine was investigated in reaction with selenium dioxide in order to obtain 4,7-dibromo-[1,2,5]selenadiazolo[3,4-d]pyridazine. We found that 7-bromo-[1,2,5]selenadiazolo[3,4-d [...] Read more.
New heterocyclic systems containing 1,2,5-chalcogenadiazoles are of great interest for the creation of organic photovoltaic materials and biologically active compounds. In this communication, 3,6-dibromopyridazine-4,5-diamine was investigated in reaction with selenium dioxide in order to obtain 4,7-dibromo-[1,2,5]selenadiazolo[3,4-d]pyridazine. We found that 7-bromo-[1,2,5]selenadiazolo[3,4-d]pyridazin-4(5H)-one, the first representative of the new heterocyclic system, was isolated as a hydrolysis product of the corresponding 4,7-dibromoderivative. The structure of the newly synthesized compound was established by means of elemental analysis, high-resolution mass spectrometry, 1H, 13C NMR, IR and UV spectroscopy, and mass spectrometry. Full article
(This article belongs to the Special Issue Heteroatom Rich Organic Heterocycles)
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Short Note
1-Methyl-8-phenyl-1,3-diazaspiro[4.5]decane-2,4-dione
Molbank 2021, 2021(2), M1228; https://0-doi-org.brum.beds.ac.uk/10.3390/M1228 - 04 Jun 2021
Viewed by 578
Abstract
A simple, fast and cost-effective three-step synthesis of 1-methyl-8-phenyl-1,3-diazaspiro[4.5]decane-2,4-dione has been developed. The reactions described herein proceed readily, with high yields and no further purification. Therefore, the proposed method, with an overall yield of 60%, offers a facile pathway to the synthesis of [...] Read more.
A simple, fast and cost-effective three-step synthesis of 1-methyl-8-phenyl-1,3-diazaspiro[4.5]decane-2,4-dione has been developed. The reactions described herein proceed readily, with high yields and no further purification. Therefore, the proposed method, with an overall yield of 60%, offers a facile pathway to the synthesis of N-1 monosubstituted spiro carbocyclic imidazolidine-2,4-diones (hydantoins), which constitute a privileged class of heterocyclic scaffolds with pharmacological interest. Full article
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Short Note
4-[(2,4-Dichlorophenyl)carbamoyl]butanoic Acid
Molbank 2021, 2021(2), M1227; https://0-doi-org.brum.beds.ac.uk/10.3390/M1227 - 04 Jun 2021
Cited by 1 | Viewed by 650
Abstract
The synthesis and spectroscopic characterization of the glutaric acid-amide derivative, 2,4-Cl2C6H3N(H)C(=O)(CH2)3C(=O)OH (1), are described. The X-ray crystal structure determination of (1) shows the backbone of the molecule to be [...] Read more.
The synthesis and spectroscopic characterization of the glutaric acid-amide derivative, 2,4-Cl2C6H3N(H)C(=O)(CH2)3C(=O)OH (1), are described. The X-ray crystal structure determination of (1) shows the backbone of the molecule to be kinked about the methylene-C–N(amide) bond as seen in the C(p)–N–C(m)–C(m) torsion angle of −157.0(2)°; m = methylene and p = phenyl. An additional twist in the molecule is noted between the amide and phenyl groups as reflected in the C(m)–N–C(p)–C(p) torsion angle of 138.2(2)°. The most prominent feature of the molecular packing is the formation of supramolecular tapes assembled through carboxylic acid-O–HO(carbonyl) and amide-N–HO(amide) hydrogen bonding. Full article
(This article belongs to the Section Structure Determination)
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Short Note
(E)-1-(3,4-Dimethoxyphenyl)-2-methyl-3-phenylprop-2-en-1-one: A P-Type Acid-Stable Photochromic α-Methylchalcone
Molbank 2021, 2021(2), M1226; https://0-doi-org.brum.beds.ac.uk/10.3390/M1226 - 04 Jun 2021
Viewed by 797
Abstract
The α-methylated chalcone 3 with an electron-donor substituted A-aryl ring and an unsubstituted B-phenyl ring was synthesized by base-catalyzed aldehyde/acetophenone condensation. Compound 3 can be photo-switched from E→Z by irradiation with long-wavelength light λ > 350 nm, whereas irradiation with shorter wavelengths leads [...] Read more.
The α-methylated chalcone 3 with an electron-donor substituted A-aryl ring and an unsubstituted B-phenyl ring was synthesized by base-catalyzed aldehyde/acetophenone condensation. Compound 3 can be photo-switched from E→Z by irradiation with long-wavelength light λ > 350 nm, whereas irradiation with shorter wavelengths leads to photo-stationary states (PSS) with lower amounts of the Z-isomer. The limiting wavelength for fully equilibrated E⮀Z (PSS = 1) can be achieved around 240 nm. The stability of both E- and Z-isomers at the wavelength-dependent PSS under UV-irradiation between 250 and 350 nm is remarkably high as observed from UV and NMR spectroscopy. Compound 3 is fatigue resistant even after more than 10 days continuous irradiation and is also oxygenation-stable under singlet oxygen sensitization conditions. In remarkable contrast to many other α-methylated chalcones, no change in the E/Z-ratio was detected when PSS samples were treated with Broensted acids. The negative photochromic E→Z switch of 3 is accompanied by a conformational switch from the E-form in its preferred s-trans conformation to the Z-form in a distorted s-cis conformation (Es-c→Zs-t). Full article
(This article belongs to the Section Organic Synthesis)
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Short Note
2-{3,5-Bis-[5-(3,4-didodecyloxyphenyl)thien-2-yl]phenyl}-5-(3,4-didodecyloxyphenyl)thiophene
Molbank 2021, 2021(2), M1225; https://0-doi-org.brum.beds.ac.uk/10.3390/M1225 - 01 Jun 2021
Viewed by 614
Abstract
Star-shaped compounds are widely recognized as emerging materials for optical and electrical applications and as scaffolds of discotic liquid crystal. While the C3-symmetrical tri(phenylthienyl)benzene is the core for several electroopotical materials, no liquid crystal with this scaffold has yet been reported. [...] Read more.
Star-shaped compounds are widely recognized as emerging materials for optical and electrical applications and as scaffolds of discotic liquid crystal. While the C3-symmetrical tri(phenylthienyl)benzene is the core for several electroopotical materials, no liquid crystal with this scaffold has yet been reported. Acid-catalyzed cyclocondensation of bromoacetylthiophene gives a C3-symmetrical star, threefold Suzuki coupling results in extension of the conjugated system. With 3,4-didodecylocyphenyl boronic acid, a star with a large rigid conjugated system and flexible aliphatic periphery is obtained. Differentials scanning calorimetry and polarized optical microscopy reveal an enantiotropic mesophase from 66 °C to 106 °C. Full article
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Communication
1,2-Bis(4-(1,3-dioxolan-2-yl)phenyl)diazene Oxide
Molbank 2021, 2021(2), M1224; https://0-doi-org.brum.beds.ac.uk/10.3390/M1224 - 01 Jun 2021
Viewed by 679
Abstract
A simple approach to synthesizing 1,2-bis(4-(1,3-dioxolan-2-yl)phenyl)diazene oxide was developed in this study, based on glucose as an eco-friendly reductant. Full article
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Short Note
Diethyl (2-(4-Phenyl-1H-1,2,3-triazol-1-yl)benzyl) Phosphate
Molbank 2021, 2021(2), M1223; https://0-doi-org.brum.beds.ac.uk/10.3390/M1223 - 01 Jun 2021
Viewed by 654
Abstract
Here we describe a full structural elucidation of the diethyl (2-(4-phenyl-1H-1,2,3-triazol-1-yl)benzyl) phosphate. This compound is a common by-product present in the synthetic protocols to access the α-hydroxy phosphonate compounds through of a Phospha-Brook rearrangement. Thus, a complete NMR structural characterization [...] Read more.
Here we describe a full structural elucidation of the diethyl (2-(4-phenyl-1H-1,2,3-triazol-1-yl)benzyl) phosphate. This compound is a common by-product present in the synthetic protocols to access the α-hydroxy phosphonate compounds through of a Phospha-Brook rearrangement. Thus, a complete NMR structural characterization of this rearrangement by-product was performed by 1H, 13C{1H}, 31P{1H}, COSY, HSQC, and HMBC NMR experiments. Additionally, we have demonstrated that the 1H-31P HMBC is a 2D heteroatom NMR experiment which combines the simple identification by 31P chemical shift with the detection sensitivity by 1H spectrum in a practical procedure. Full article
(This article belongs to the Section Structure Determination)
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Communication
Synthesis and Cytotoxic Potential of 3-Oxo-19β-trifluoroacetoxy-18αH-oleane-28-oic Acid
Molbank 2021, 2021(2), M1222; https://0-doi-org.brum.beds.ac.uk/10.3390/M1222 - 01 Jun 2021
Viewed by 660
Abstract
Trifluoroacetic acid-promoted Wagner-Meerwein rearrangement of betulonic acid carboxamide led to the formation of the expected 19β,28-lactam along with a new germanicane-type 3-oxo-19β-trifluoroacetoxy-18αH-oleane-28-oic acid. The structure of this triterpenoid was confirmed by 2D NMR analyses. A primary evaluation of biological potency revealed [...] Read more.
Trifluoroacetic acid-promoted Wagner-Meerwein rearrangement of betulonic acid carboxamide led to the formation of the expected 19β,28-lactam along with a new germanicane-type 3-oxo-19β-trifluoroacetoxy-18αH-oleane-28-oic acid. The structure of this triterpenoid was confirmed by 2D NMR analyses. A primary evaluation of biological potency revealed an anticancer activity with GI50 < 5 μM against leukemia, colon cancer, breast cancer, and prostate cancer cell lines, while the parent compounds were not active. Full article
(This article belongs to the Section Natural Products)
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Short Note
2-Cyclopropyl-6-phenyl-2,3-dihydrothieno[3,2-d][1,3,2]diazaborinin-4(1H)-one
Molbank 2021, 2021(2), M1221; https://0-doi-org.brum.beds.ac.uk/10.3390/M1221 - 01 Jun 2021
Viewed by 781
Abstract
As part of our ongoing scaffold hopping work on antimalarial 2-aminothieno[3,2-d]pyrimidin-4-one scaffold, we explored the dihydrothieno[3,2-d][1,3,2]diazaborinin-4(1H)-one as a potential new antimalarial series. Using conditions found in the literature, we obtained 2-cyclopropyl-6-phenyl-2,3-dihydrothieno[3,2-d][1,3,2]diazaborinin-4(1H)-one with 93% [...] Read more.
As part of our ongoing scaffold hopping work on antimalarial 2-aminothieno[3,2-d]pyrimidin-4-one scaffold, we explored the dihydrothieno[3,2-d][1,3,2]diazaborinin-4(1H)-one as a potential new antimalarial series. Using conditions found in the literature, we obtained 2-cyclopropyl-6-phenyl-2,3-dihydrothieno[3,2-d][1,3,2]diazaborinin-4(1H)-one with 93% yield through a simple treatment. It was then characterized by NMR (1H and 13C) and HRMS. Given the structure of this molecule, its aqueous stability was assessed to determine its suitability for biological tests. To our knowledge, this is the first dihydrothieno[3,2-d][1,3,2]diazaborinin-4(1H)-one described. Full article
(This article belongs to the Section Organic Synthesis)
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(2S*,4S*)-4-[(E)-(2,2-Dimethylhydrazono)methyl]-6-methoxy-4-methyl-2-[(E)-styryl]-1,2,3,4-tetrahydroquinoline
Molbank 2021, 2021(2), M1220; https://0-doi-org.brum.beds.ac.uk/10.3390/M1220 - 01 Jun 2021
Viewed by 628
Abstract
The Povarov reaction of p-anisidine, cinnamaldehyde and methacrolein dimethylhydrazone afforded a 1,2,3,4-tetrahydroquinoline derivative bearing 2-styryl, 4-methyl and 4-dimethylhydrazono substituents in a fully diastereoselective fashion. This is the first example of the combination of a type I aza-vinylogous Povarov reaction and a type [...] Read more.
The Povarov reaction of p-anisidine, cinnamaldehyde and methacrolein dimethylhydrazone afforded a 1,2,3,4-tetrahydroquinoline derivative bearing 2-styryl, 4-methyl and 4-dimethylhydrazono substituents in a fully diastereoselective fashion. This is the first example of the combination of a type I aza-vinylogous Povarov reaction and a type II vinylogous Povarov reaction in the same process. Full article
(This article belongs to the Special Issue Quinoline, Derivatives and Applications)
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Communication
Ammonium Salts of 5-(3-Chromenyl)-5H-chromeno[2,3-b]pyridines
Molbank 2021, 2021(2), M1219; https://0-doi-org.brum.beds.ac.uk/10.3390/M1219 - 30 May 2021
Viewed by 727
Abstract
The ammonium salts of many drugs have significantly improved the solubility and, accordingly, the bioavailability of medicinal substances in the human body. 5-(4-Hydroxy-2-oxo-2H-chromen-3-yl)-5H-chromeno[2,3-b]pyridines are potential NPY1R ligands, which are attractive for antiobesity treatment. Ammonium salts of 5 [...] Read more.
The ammonium salts of many drugs have significantly improved the solubility and, accordingly, the bioavailability of medicinal substances in the human body. 5-(4-Hydroxy-2-oxo-2H-chromen-3-yl)-5H-chromeno[2,3-b]pyridines are potential NPY1R ligands, which are attractive for antiobesity treatment. Ammonium salts of 5H-chromeno[2,3-b]pyridines were previously unknown. In this communication, it was found that the four-component reaction of salicylaldehyde, 2-aminoprop-1-ene-1,1,3-tricarbonitrile, 4-Hydroxy-2H-chromen-2-one and amines results in the formation of ammonium salts of 5-(3-chromenyl)-5H-chromeno[2,3-b]pyridines. The structure of these previously unknown compounds was confirmed by means of 1H, 13C NMR and IR spectroscopy, mass spectrometry and elemental analysis. Full article
(This article belongs to the Section Organic Synthesis)
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5-Ethoxy-1-(4-methoxyphenyl)-5-methyl-3-phenylimidazolidine-2,4-dione
Molbank 2021, 2021(2), M1218; https://0-doi-org.brum.beds.ac.uk/10.3390/M1218 - 28 May 2021
Viewed by 788
Abstract
The title compound is a hydantoin derivative that has been synthesized through a three-component reaction of ethyl pyruvate, p-anisidine and phenyl isocyanate. This paper provides a comprehensive spectral dataset for the title compound, including 1H and 13C{1H} NMR, [...] Read more.
The title compound is a hydantoin derivative that has been synthesized through a three-component reaction of ethyl pyruvate, p-anisidine and phenyl isocyanate. This paper provides a comprehensive spectral dataset for the title compound, including 1H and 13C{1H} NMR, IR, HRMS, and X-ray crystallography analyses. A tentative mechanism comprising two complementary pathways is provided based on additional experiments with the preformed intermediates. Full article
(This article belongs to the Section Organic Synthesis)
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Dichloro(η6-p-cymene)(P,P-diphenyl-N-propyl-phosphinous amide-κP)ruthenium(II)
Molbank 2021, 2021(2), M1217; https://0-doi-org.brum.beds.ac.uk/10.3390/M1217 - 28 May 2021
Viewed by 696
Abstract
The title compound, i.e., [RuCl2(η6-p-cymene)(PPh2NHnPr)] (2), was obtained in a 71% yield by reacting a toluene solution of the chlorophosphine complex [RuCl2(η6-p-cymene)(PPh2 [...] Read more.
The title compound, i.e., [RuCl2(η6-p-cymene)(PPh2NHnPr)] (2), was obtained in a 71% yield by reacting a toluene solution of the chlorophosphine complex [RuCl2(η6-p-cymene)(PPh2Cl)] (1) with two equivalents of n-propylamine at room temperature. The aminophosphine complex 2 was characterized by elemental analysis, multinuclear NMR (31P{1H}, 1H and 13C{1H}) and IR spectroscopy. In addition, its catalytic behavior in the hydration of benzonitrile was briefly explored. Full article
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Trans-[Cu(quin)2(EtOH)2]
Molbank 2021, 2021(2), M1216; https://0-doi-org.brum.beds.ac.uk/10.3390/M1216 - 27 May 2021
Viewed by 852
Abstract
Trans-[Cu(quin)2(EtOH)2] (1) was synthesized as part of our study on copper(II) quinaldinate complexes with various O- and N-donor ligands. Compound 1 was characterized by infrared spectroscopy, thermal analysis and X-ray structure analysis. Full article
(This article belongs to the Section Structure Determination)
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Communication
Synthesis, Characterization, and DFT Studies of N-(3,5-Bis(trifluoromethyl)benzyl)stearamide
Molbank 2021, 2021(2), M1215; https://0-doi-org.brum.beds.ac.uk/10.3390/M1215 - 25 May 2021
Viewed by 525
Abstract
The novel N-(3,5-bis(trifluoromethyl)benzyl)stearamide 3 was prepared in moderate yield by a solventless direct amidation reaction of stearic acid 1 with 3,5-bis(trifluoromethyl)benzylamine 2 at 140 °C for 24 h under metal- and catalyst-free conditions. This practical method was conducted [...] Read more.
The novel N-(3,5-bis(trifluoromethyl)benzyl)stearamide 3 was prepared in moderate yield by a solventless direct amidation reaction of stearic acid 1 with 3,5-bis(trifluoromethyl)benzylamine 2 at 140 °C for 24 h under metal- and catalyst-free conditions. This practical method was conducted in air without any special treatment or activation. The fatty acid amide 3 was fully characterized by IR, UV–Vis, 1D and 2D NMR spectroscopy, mass spectrometry, and elemental analysis. Moreover, molecular electrostatic potential studies, determination of quantum descriptors, fundamental vibrational frequencies, and intensity of vibrational bands were computed by density functional theory (DFT) using the B3LYP method with 6-311+G(d,p) basis set in gas phase. Simulation of the infrared spectrum using the results of these calculations led to good agreement with the observed spectral patterns. Full article
(This article belongs to the Section Organic Synthesis)
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3′-Methyl-2-oxo-1′,5′-diphenyl-1′,7′-dihydrospiro[indoline-3,4′-pyrazolo[3,4-b]pyridine]-6′-carboxylic Acid
Molbank 2021, 2021(2), M1214; https://0-doi-org.brum.beds.ac.uk/10.3390/M1214 - 21 May 2021
Viewed by 483
Abstract
3′-methyl-2-oxo-1′,5′-diphenyl-1′,7′-dihydrospiro[indoline-3,4′-pyrazolo[3,4-b]pyridine]-6′-carboxylic acid was synthesized using diverse conditions. The best reaction condition consisted of using water as solvent under microwave irradiation, affording product in 76% yield. Full article
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N-[7-Chloro-4-[4-(phenoxymethyl)-1H-1,2,3-triazol-1-yl]quinoline]-acetamide
Molbank 2021, 2021(2), M1213; https://0-doi-org.brum.beds.ac.uk/10.3390/M1213 - 20 May 2021
Viewed by 601
Abstract
The 1,2,3-triazole is a well-known biologically active pharmacophore constructed by the copper-catalyzed azide–alkyne cycloaddition. We herein reported the synthesis of 4-amino-7-chloro-based [1,2,3]-triazole hybrids via Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition of 4-azido-7-chloroquinoline with an alkyne derivative of acetaminophen. The compound was fully characterized by Fourier-transform [...] Read more.
The 1,2,3-triazole is a well-known biologically active pharmacophore constructed by the copper-catalyzed azide–alkyne cycloaddition. We herein reported the synthesis of 4-amino-7-chloro-based [1,2,3]-triazole hybrids via Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition of 4-azido-7-chloroquinoline with an alkyne derivative of acetaminophen. The compound was fully characterized by Fourier-transform infrared (FTIR), proton nuclear magnetic resonance (1H-NMR), carbon-13 nuclear magnetic resonance (13C-NMR), heteronuclear single quantum coherence (HSQC), ultraviolet (UV) and high-resolution mass spectroscopies (HRMS). This compound was screened in vitro with different normal and cancer cell lines. The drug likeness of the compound was also investigated by predicting its pharmacokinetic properties. Full article
(This article belongs to the Special Issue Synthesis of Flavonoids or Other Nature-Inspired Small Molecules)
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(E)-3-((2-Fluorophenyl)(hydroxy)methylene)imidazo[1,2-a]pyridin-2(3H)-one
Molbank 2021, 2021(2), M1212; https://0-doi-org.brum.beds.ac.uk/10.3390/M1212 - 14 May 2021
Viewed by 528
Abstract
Treatment of a N-2-pyridyl-β-ketoamide precursor with bromine afforded the first example of the 3-aryl(α-hydroxy)methylenelimidazo[1,2-a]pyridin-2(3H)-one framework. This transformation proceeded through a domino process comprising an initial bromination, cyclization via an intramolecular SN reaction, and a final keto-enol tautomerism, and [...] Read more.
Treatment of a N-2-pyridyl-β-ketoamide precursor with bromine afforded the first example of the 3-aryl(α-hydroxy)methylenelimidazo[1,2-a]pyridin-2(3H)-one framework. This transformation proceeded through a domino process comprising an initial bromination, cyclization via an intramolecular SN reaction, and a final keto-enol tautomerism, and allows generation of the fused heterocyclic system and installation of the acyl substituent in a single operation. Full article
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N-(3-Cyano-4,5,6,7-tetrahydrobenzothiophen-2-yl)-2-[[5-[(1,5-dimethyl-3-oxo-2-phenylpyrazol-4-yl)amino]-1,3,4-thiadiazol-2-yl]sulfanyl]acetamide
Molbank 2021, 2021(2), M1211; https://0-doi-org.brum.beds.ac.uk/10.3390/M1211 - 10 May 2021
Viewed by 818
Abstract
The small pyrazolone-bearing molecules attract attention and are widely explored in drug design as pharmacological agents. The new pyrazolone-thiadiazole hybrid molecule N-(3-cyano-4,5,6,7-tetrahydrobenzothiophen-2-yl)-2-[[5-[(1,5-dimethyl-3-oxo-2-phenylpyrazol-4-yl)amino]-1,3,4-thiadiazol-2-yl]sulfanyl]acetamide (3) has been synthesized following a two-stage protocol using simple, convenient transformations and cheap, commercially available reagents. The [...] Read more.
The small pyrazolone-bearing molecules attract attention and are widely explored in drug design as pharmacological agents. The new pyrazolone-thiadiazole hybrid molecule N-(3-cyano-4,5,6,7-tetrahydrobenzothiophen-2-yl)-2-[[5-[(1,5-dimethyl-3-oxo-2-phenylpyrazol-4-yl)amino]-1,3,4-thiadiazol-2-yl]sulfanyl]acetamide (3) has been synthesized following a two-stage protocol using simple, convenient transformations and cheap, commercially available reagents. The compound’s structure was confirmed using 1H, 13C nuclear magnetic resonance (NMR), and liquid chromatography–mass spectrometry (LC–MS) spectra. The anti-inflammatory potency of 3 was evaluated in silico using molecular docking. The docking studies results suggest that title compound 3 is of great interest for further structure optimization and in-depth studies as a possible 5-lipoxygenase (5-LOX) inhibitor. Full article
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Communication
Palladium-Catalyzed Direct Mono- and Diarylation of Diphenydithienylethenes: A Useful Method for Enhancing Fluorescence Intensity and Aggregation-Induced Emission
Molbank 2021, 2021(2), M1210; https://0-doi-org.brum.beds.ac.uk/10.3390/M1210 - 10 May 2021
Viewed by 548
Abstract
In this study we report efficient method for the syntheses of mono- and diarylated diphenyldithienylethene (DPDTE) via a palladium-catalyzed C–H arylation reaction. These new derivatives showed amplified luminescent properties thanks to a change in polarity, particularly in the presence of an electron-withdrawing groups [...] Read more.
In this study we report efficient method for the syntheses of mono- and diarylated diphenyldithienylethene (DPDTE) via a palladium-catalyzed C–H arylation reaction. These new derivatives showed amplified luminescent properties thanks to a change in polarity, particularly in the presence of an electron-withdrawing groups (EWG). Moreover, the arylated DPDTEs showed dual-emissive phenomena, including fluorescence in organic solvents and aggregation-induced emission. Full article
(This article belongs to the Section Organic Synthesis)
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4-[(4-Chlorophenyl)carbamoyl]butanoic Acid
Molbank 2021, 2021(2), M1209; https://0-doi-org.brum.beds.ac.uk/10.3390/M1209 - 06 May 2021
Cited by 1 | Viewed by 606
Abstract
The X-ray crystal structure determination of the glutaric acid-amide derivative, 4-ClC6H4N(H)C(=O)(CH2)3C(=O)OH (1), is described. The backbone of the molecule adopts an extended, all-trans configuration but the terminal carboxylic acid and phenyl resides are [...] Read more.
The X-ray crystal structure determination of the glutaric acid-amide derivative, 4-ClC6H4N(H)C(=O)(CH2)3C(=O)OH (1), is described. The backbone of the molecule adopts an extended, all-trans configuration but the terminal carboxylic acid and phenyl resides are twisted out of the plane through the bridging atoms, as seen in the torsion angles of O(carboxylic acid)–C(m)–C(m)–C(m) [13.9(5)°] and C(m)–N–C(p)–C(p) [47.1(4)°]; m = methylene and p = phenyl. The most striking feature of the molecular packing is the formation of supramolecular tapes mediated by carboxylic acid-O–H⋯O(carbonyl) and amide-N–H⋯O(amide) hydrogen bonding. Full article
(This article belongs to the Section Structure Determination)
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