Fluorinated benzimidazole derivatives: In vitro antimicrobial activity

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 four Gram-positive bacteria, two Gram-negative bacteria and two 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 which hold fluorine atom in meta-positions of phenyl ring side chain of benzimidazole 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 the discovery and optimization of novel antimicrobial agents.