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

Olayinka Oyewale Ajani (Department of Chemistry, College of Science and Technology, Covenant University, Canaanland, Km 10 Idiroko Road, P.M.B. 1023, Ota, Ogun State, Nigeria)
Olaoluwasubomi Eneyeme Joseph (Department of Chemistry, College of Science and Technology, Covenant University, Canaanland, Km 10 Idiroko Road, P.M.B. 1023, Ota, Ogun State, Nigeria)
King Tamunodikibugerere Iyaye (Department of Chemistry, College of Science and Technology, Covenant University, Canaanland, Km 10 Idiroko Road, P.M.B. 1023, Ota, Ogun State, Nigeria)
Natasha October (Department of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria, 0002, South Africa)
Damilola Victoria Aderohunmu (Department of Chemistry, College of Science and Technology, Covenant University, Canaanland, Km 10 Idiroko Road, P.M.B. 1023, Ota, Ogun State, Nigeria)
Shade John Olorunshola (Department of Biological Science, College of Science and Technology, Covenant University, Canaanland, Km 10 Idiroko Road, P.M.B. 1023, Ota, Ogun State, Nigeria)
Oluwatosin Yemisi Audu (Department of Chemistry, University of Pretoria, Lynnwood Road, Hatfield, Pretoria, 0002, South Africa)

Indonesian Journal of Chemistry
Vol 20, No 1 (2020)

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.