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Article

Investigations into the Structure/Antibacterial Activity Relationships of Cyclam and Cyclen Derivatives

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Centro de Química Estrutural, Associação do Instituto Superior Técnico para a Investigação e Desenvolvimento, 1049-003 Lisboa, Portugal
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IBB-Instituto de Bioengenharia e Biociências, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
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Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
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BioISI—Biosystems & Integrative Sciences Institute, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
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CERENA—Centro de Recursos Naturais e Ambiente, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
*
Authors to whom correspondence should be addressed.
Received: 22 October 2019 / Revised: 8 November 2019 / Accepted: 12 November 2019 / Published: 14 November 2019
A series of cyclam- and cyclen-derived salts are described in the present work; they were designed specifically to gain insights into their structure and antibacterial activity towards Staphylococcus aureus and Escherichia coli, used respectively, as Gram-positive and Gram-negative model organisms. The newly synthesized compounds are monosubstituted and trans-disubstituted tetraazamacrocycles that display benzyl, methylbenzyl, trifluoromethylbenzyl, or trifluoroethylbenzyl substituents appended on the nitrogen atoms of the macrocyclic ring. The results obtained show that the chemical nature, polarity, and substitution patterns of the benzyl groups, as well as the number of pendant arms, are critical parameters for the antibacterial activity of the cyclam-based salts. The most active compounds against both bacterial strains were the trans-disubstituted cyclam salts displaying CF3 groups in the para-position of the aromatic rings of the macrocyclic pendant arms. The analogous cyclen species presents a lower activity, revealing that the size of the macrocyclic backbone is an important requirement for the antibacterial activity of the tetraazamacrocycles. The nature of the anionic counterparts present on the salts was found to play a minor role in the antibacterial activity. View Full-Text
Keywords: tetraazamacrocycles; Antibacterials; Azarings; E. coli; S. aureus tetraazamacrocycles; Antibacterials; Azarings; E. coli; S. aureus
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MDPI and ACS Style

Alves, L.G.; Portel, J.F.; Sousa, S.A.; Ferreira, O.; Almada, S.; Silva, E.R.; Martins, A.M.; Leitão, J.H. Investigations into the Structure/Antibacterial Activity Relationships of Cyclam and Cyclen Derivatives. Antibiotics 2019, 8, 224. https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics8040224

AMA Style

Alves LG, Portel JF, Sousa SA, Ferreira O, Almada S, Silva ER, Martins AM, Leitão JH. Investigations into the Structure/Antibacterial Activity Relationships of Cyclam and Cyclen Derivatives. Antibiotics. 2019; 8(4):224. https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics8040224

Chicago/Turabian Style

Alves, Luis G., João F. Portel, Sílvia A. Sousa, Olga Ferreira, Stephanie Almada, Elisabete R. Silva, Ana M. Martins, and Jorge H. Leitão 2019. "Investigations into the Structure/Antibacterial Activity Relationships of Cyclam and Cyclen Derivatives" Antibiotics 8, no. 4: 224. https://0-doi-org.brum.beds.ac.uk/10.3390/antibiotics8040224

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