Bioorganic and Medicinal Chemistry Reports

Given the pharmacological significance of fluorine-containing heterocycles, in the present paper, a series of benzimidazole having fluoro-benzene moiety within a single molecular framework were screened for their in vitro antimicrobial activity against some Gram-positive and Gram-negative bacteria and fungal strains. The results of antimicrobial activity demonstrated that fluoro-substituted compounds (13-15 and 17-19) have good antibacterial and antifungal properties as compared to unsubstituted parent compounds (12 and 16). Compound 18 with meta-fluoro substitution group on the phenyl ring of the side chain displayed high activity against Gram-negative bacteria with a MIC value of 31.25 μg/mL. Similarly, 2-(m-fluorophenyl)-benzimidazole derivatives 14 and 18 showed good anti-B. subtilis with a MIC value of 7.81 μg/mL. SAR studies suggested that the presence of methyl substitution group at position 5 of benzimidazole is recommended for significant antifungal activity against C. parapsilosis. The high potency suggested that compound 18 could be a starting point for further optimization to develop novel antimicrobial agents.