Abstract

Benzimidazole scaffolds are structural isosteres of naturally occurring nucleotides which allows them to interact with the biopolymers and enzymatic sites of living systems. The aim of this present work is to synthesize selected 2-alkanamino-benzimidazole derivatives in order to investigate their antimicrobial efficiency for possible future drug development. The series of targeted compounds were conventionally synthesized in good to excellent yields via [4+1]-cyclo-addition of o-phenylenediamine with some L-amino acid and purified by recrystallization or column chromatography where necessary. The chemical structures were confirmed by physico-chemical and spectral data which include UV, IR, 1H- and 13C-NMR. In addition, the antimicrobial properties of the synthesized benzimidazole derivatives were determined on six bacteria isolates alongside with gentamycin standard drug using agar diffusion method. The synthesized compounds showed broader activities spectrum than gentamycin and (1H-benzo[d]imidazol-2-yl)methanamine, 10a emerged as the most potent. Based on the versatility of the synthetic pathway and improved antibacterial activity, these compounds are recommended as good candidates for further studies in terms of MIC test, toxicity profile as some of them might pave way in the pharmaceutical research for future drug design.

Key words: Benzimidazole, cyclo-addition, zone of inhibition, spectroscopy, drug design.