Antimicrobial evaluation of cinnamic and benzoic haloamides

This study aimed to prepare a collection of para-halogenated benzylamides derivatives of structurally related benzoic and cinnamic acids by coupling reactions with 4-halobenzylamines, using BOP as a coupling agent. All compounds obtained were submitted to antimicrobial tests, using the method of the minimum inhibitory concentration (MIC), with gentamicin, amikacin, norfloxacin, penicillin as controls in the antibacterial assays. The study led to 22 amides (1-22) with yields ranging from 29-89%. Those compounds were confirmed by infrared spectra, 1H and 13C NMR spectra and by high resolution mass spectroscopy. The antimicrobial evaluation showed that only compound 4 have antibacterial activity and no amide derivative of vanillic acid showed biological activity. We conclude that antimicrobial assays of 4-methoxycinnamic acid derivatives may reveal new antibacterial agents.