Synthesis and in vitro antimicrobial activity of some novel substituted benzimidazole derivatives having potent activity against MRSA.

The novel benzimidazole derivatives (3, 5, 8, 9, 12-14, 18-41) were prepared in this paper and the antimicrobial activities of these compounds against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA, standard and clinical isolates), Bacillus subtilis, Escherichia coli and Candida albicans were evaluated. Compounds 24-26 which have no substitution of N-1 position displayed better antibacterial activities than those of standards (ciprofloxacin, ampicillin and sultamicillin) against both the drug-resistant bacteria (MRSA, standard and clinical isolates). These derivatives (24-26), 2,5,6-trihalogenobenzimidazole analogues (8, 12), 5,6-dichloro-2-amino derivative (13), and 5-chloro-2-(4-benzyloxyphenyl)benzimidazole (35) exhibited the most potent antibacterial activity with MIC 3.12 microg/ml against S. aureus.