Pyrazine-2-substituted carboxamide derivatives: synthesis, antimicrobial and Leuconostoc mesenteroides growth inhibition activity

Condensation of pyrazine-2,3-dicarboxylic acid anhydride with aminoacetophenones gave the corresponding N-(acetylphenyl)pyrazine-2-carboxamide. Their reactions with some electrophilic (carbonyl group, bromine) and nucleophilic (malononitrile, hydrazine) reagents are discussed. N-[3-(2,2-Dicyano-1-methyl- ethenyl)phenyl]pyrazine-2-carboxamide underwent Michael addition reaction with an activated double bond yielding 3-amino-5-aryl-3’-(pyrazine-2-carboxamido)bi- phenyl-2,4-dicarbonitrile derivatives and 2-imino-4-(3-(pyrazine-2-carboxamido)phenyl)-6-(4-methoxyphenyl)cyclohexa-3,5-diene-1,1,3-tricarbonitrile. The structures of the newly synthesized compounds were confirmed by their IR, 1H NMR, 13C NMR and mass spectra data. Antimicrobial acitivites and Leuconostoc sp. growth inhibition of the newly synthesized compounds were studied and some of these were found to exhibit a pronounced effect