A series of substituted N-benzyl-3-chloropyrazine-2-carboxamides were prepared as positional isomers of 5-chloro and 6-chloro derivatives, prepared previously. During the aminolysis of the acyl chloride, the simultaneous substitution of chlorine with benzylamino moiety gave rise to N-benzyl-3-(benzylamino)pyrazine-2-carboxamides as side products, in some cases. Although not initially planned, the reaction conditions were modified to populate this double substituted series. The final compounds were tested against four mycobacterial strains. N-(2-methylbenzyl)-3-((2-methylbenzyl)amino)pyrazine-2-carboxamide (1a) and N-(3,4-dichlorobenzyl)-3-((3,4-dichlorobenzyl)amino)pyrazine-2-carboxamide (9a) proved to be the most effective against Mycobacterium tuberculosis H37Rv, with MIC = 12.5 μg·mL-1. Compounds were screened for antibacterial activity. The most active compound was 3-chloro-N-(2-chlorobenzyl)pyrazine-2-carboxamide (5) against Staphylococcus aureus with MIC = 7.81 μM, and Staphylococcus epidermidis with MIC = 15.62 μM. HepG2 in vitro cytotoxicity was evaluated for the most active compounds; however, no significant toxicity was detected. Compound 9a was docked to several conformations of the enoyl-ACP-reductase of Mycobacterium tuberculosis. In some cases, it was capable of H-bond interactions, typical for most of the known inhibitors.

Department of Clinical Microbiology University Hospital Sokolská 581 500 05 Hradec Králové Czech Republic

Faculty of Pharmacy in Hradec Králové Charles University Heyrovského 1203 500 05 Hradec Králové Czech Republic

See more in PubMed

O’Connell K.M.G., Hodgkinson J.T., Sore H.F., Welch M., Salmond G.P.C., Spring D.R. Combating Multidrug-Resistant Bacteria: Current Strategies for the Discovery of Novel Antibacterials. Angew. Chem. Int. Ed. 2013;52:10706–10733. doi: 10.1002/anie.201209979. PubMed DOI

World Health Organisation . Global Action Plan on Antimicrobial Resistance. World Health Organisation; Geneva, Switzerland: 2015. [(accessed on 16 January 2017)]. WHA68/2015/REC/1. Available online: http://www.who.int/antimicrobial-resistance/publications/global-action-plan/en/

World Health Organization . Global Tuberculosis Report 2016. World Health Organisation; Geneva, Switzerland: 2016. [(accessed on 16 January 2017)]. WHA68/2015/REC/1. Available online: http://www.who.int/tb/publications/global_report/en/

Servusova-Vanaskova B., Jandourek O., Paterova P., Kordulakova J., Plevakova M., Kubicek V., Kucera R., Garaj V., Naesens L., Kunes J., et al. Alkylamino derivatives of N-Benzylpyrazine-2-carboxamide: Synthesis and antimycobacterial evaluation. MedChemComm. 2015;6:1311–1317. doi: 10.1039/C5MD00178A. DOI

Lima C.H.S., Henriques M.G.M.O., Candea A.L.P., Lourenco M.C.S., Bezerra F.A.F.M., Ferreira M.L., Kaiser C.R., de Souza M.V.N. Synthesis and Antimycobacterial Evaluation of N′-(E)-heteroaromaticpyrazine-2-carbohydrazide Derivatives. Med. Chem. 2011;7:245–249. doi: 10.2174/157340611795564303. PubMed DOI

Zimhony O., Vilcheze C., Arai M., Welch J.T., Jacobs W.R. Pyrazinoic acid and its n-propyl ester inhibit fatty acid synthase type I in replicating tubercle bacilli. Antimicrob. Agents Chemother. 2007;51:752–754. doi: 10.1128/AAC.01369-06. PubMed DOI PMC

Fernandes J.P.D., Pavan F.R., Leite C.Q.F., Felli V.M.A. Synthesis and evaluation of a pyrazinoic acid prodrug in Mycobacterium tuberculosis. Saudi Pharm. J. 2014;22:376–380. doi: 10.1016/j.jsps.2013.12.005. PubMed DOI PMC

Singh P., Mishra A.K., Malonia S.K., Chauhan D.S., Sharma V.D., Venkatesan K., Katoch V.M. The paradox of pyrazinamide: An update on the molecular mechanisms of pyrazinamide resistance in Mycobacteria. J. Commun. Dis. 2006;38:288–298. PubMed

Shi W., Zhang X., Jiang X., Yuan H., Lee J.S., Barry C.E, III, Wang H., Zhang W., Zhang Y. Pyrazinamide Inhibits Trans-Translation in Mycobacterium tuberculosis. Science. 2011;333:1630–1632. doi: 10.1126/science.1208813. PubMed DOI PMC

Sayahi H., Pugliese K.M., Zimhony O., Jacobs W.R., Jr., Shekhtman A., Welch J.T. Analogs of the Antituberculous Agent Pyrazinamide Are Competitive Inhibitors of NADPH Binding to M. tuberculosis Fatty Acid Synthase I. Chem. Biodivers. 2012;9:2582–2596. doi: 10.1002/cbdv.201200291. PubMed DOI

Shi W., Chen J., Feng J., Cui P., Zhang S., Weng X., Zhang W., Zhang Y. Aspartate decarboxylase (PanD) as a new target of pyrazinamide in Mycobacterium tuberculosis. Emerg. Microbes Infect. 2014;3:e58. doi: 10.1038/emi.2014.61. PubMed DOI PMC

Kalinda A.S., Aldrich C.C. Pyrazinamide: A Frontline Drug Used for Tuberculosis. Molecular Mechanism of Action Resolved after 50 Years? ChemMedChem. 2012;7:558–560. doi: 10.1002/cmdc.201100587. PubMed DOI

Servusova B., Eibinova D., Dolezal M., Kubicek V., Paterova P., Pesko M., Kral’ova K. Substituted N-Benzylpyrazine-2-carboxamides: Synthesis and Biological Evaluation. Molecules. 2012;17:13183–13198. doi: 10.3390/molecules171113183. PubMed DOI PMC

Servusova B., Vobickova J., Paterova P., Kubicek V., Kunes J., Dolezal M., Zitko J. Synthesis and antimycobacterial evaluation of N-substituted 5-chloropyrazine-2-carboxamides. Bioorg. Med. Chem. Lett. 2013;23:3589–3591. doi: 10.1016/j.bmcl.2013.04.021. PubMed DOI

Semelkova L., Konecna K., Paterova P., Kubicek V., Kunes J., Novakova L., Marek J., Naesens L., Pesko M., Kralova K., et al. Synthesis and Biological Evaluation of N-Alkyl-3-(alkylamino)-pyrazine-2-carboxamides. Molecules. 2015;20:8687–8711. doi: 10.3390/molecules20058687. PubMed DOI PMC

Zitko J., Dolezal M. Enoyl acyl carrier protein reductase inhibitors: An updated patent review (2011–2015) Expert Opin. Ther. Pat. 2016;26:1079–1094. doi: 10.1080/13543776.2016.1211112. PubMed DOI

Jampilek J., Dolezal M., Kunes J., Satinsky D., Raich I. Novel regioselective preparation of 5-chloropyrazine-2-carbonitrile from pyrazine-2-carboxamide and coupling study of substituted phenylsulfanylpyrazine-2-carboxylic acid derivatives. Curr. Org. Chem. 2005;9:49–60. doi: 10.2174/1385272053369312. DOI

Jandourek O., Dolezal M., Paterova P., Kubicek V., Pesko M., Kunes J., Coffey A., Guo J., Kralova K. N-Substituted 5-Amino-6-methylpyrazine-2,3-dicarbonitriles: Microwave-Assisted Synthesis and Biological Properties. Molecules. 2014;19:651–671. doi: 10.3390/molecules19010651. PubMed DOI PMC

Towards Novel 3-Aminopyrazinamide-Based Prolyl-tRNA Synthetase Inhibitors: In Silico Modelling, Thermal Shift Assay and Structural Studies

N-Pyrazinoyl Substituted Amino Acids as Potential Antimycobacterial Agents-The Synthesis and Biological Evaluation of Enantiomers

Derivatives of 3-Aminopyrazine-2-carboxamides: Synthesis, Antimicrobial Evaluation, and in Vitro Cytotoxicity