Synthesis of Some New 1H-Benzimidazole-2-carboxamido Derivatives and Their Antimicrobial Activitiy

5,6-Dichloro-2-hydroxymethyl-1H-benzimidazole (1) was prepared by the cyclization of 4,5-dichloro-o-phenylenediamine with glycolic acid, then, alcohol group of 1 was converted to carboxylic acid (2). The final products 5,6-dichloro-1H-benzimidazole-2-carboxamides (3-11, 13-14) were prepared by the amidification of compounds 2 with several amines by using O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate. Compound 12 was prepared by the reaction of compound 6 with methanolic HCl. The relations between the tautomer and nontautomer types of imidazole moiety are discussed with NMR spectroscopy. The in vitro antibacterial and antifungal activity of the synthesized compounds against S. aureus, E. coli, B. subtilis, and C. albicans were evaluated with the disc diffusion techniques. The synthesized compounds were more active against the bacteria than fungi. Compound 3 exhibited best inhibitory activity against S. aureus.