DESIGN AND BIOLOGICAL EVALUATION OF MERCAPTOBENZIMIDAZOLE DERIVATIVES AS EMERGING ANTIMICROBIAL AGENTS

Benzimidazoles are a group of hererocyclic compounds having excessive structural flexibility, physicochemical stability, as well as promising biological activities. A series of 1, 2-disubstituted mercaptobenzimidazole derivatives has been synthesized by the nucleophilic substitution of various alkyl halides at C-2 of mercaptobenzimidazole, as a new class of compound in this study. Thin Layer Chromatography (TLC), Fourier-Transform Infrared Spectroscopy (FT-IR), and Proton Nuclear Magnetic Resonance (^1H NMR) spectroscopy were used to characterize the synthesized compounds. The produced compounds were examined for antibacterial activity against the bacteria (Staphylococcus aureus, Bacillus subtilis, and Escherich coli) using the agar well diffusion method and ciprofloxacin as a reference drug. From these synthesized derivatives, BK-3 and BK-5 have been found to possess excellent activity and the rest BK-2, BK-4, BK-6 and BK-8 exhibited good activity. The antibacterial activity of these derivatives was not superior to that of ciprofloxacin, but it suggested that 1,2-disubstituted mercaptobenzimidazole could serve as a lead for developing new antibiotics. The present study highlights the significance of the strategic substitution on benzimidazole core to enhance the biological activity and will support further structure-activity relationship (SAR) studies.