Facile Synthesis, Characterization and <i>in vitro</i> Antibacterial Efficacy of Functionalized 2-Substituted Benzimidazole Motifs

Abstract

A series of functionalized 2-substituted benzimidazole motifs was designed and successfully synthesized via thermal cyclization of 1,2-diaminobenzene on COOH end of L- leucine to achieve benzimidazole derivatives 6 as the essential precursor. The coupling of the precursor 6 with benzaldehyde derivatives a-h, ketone series i-k, and aryl sulfonyl chlorides l-n led to the formation of the targeted 2-substituted benzimidazole motifs 7a-n in improved yields. The targeted benzimidazole motifs were structurally authenticated through their spectral data and microanalytical parameters. The targeted final moieties were investigated for potential antimicrobial activity using the agar diffusion method with gentamicin as the clinical standard. All the compounds had a broad spectrum of activity with compound 7k having the highest remarkable activity with MIC of 0.98 ± 0.02 µg/mL and MBC value of 3.91 ± 0.10 µg/mL. These findings suggest that compound 7k containing camphor might be a good candidate for the design of new antimicrobial small-molecule drugs.

Keywords

• benzimidazole
• [4+1]-cycloaddition
• serial dilution
• sar study
• antibacterial