Novel benzimidazole-based thioamide derivatives as potential anticancer agents: synthesis, biological evaluation, and...

A series of novel benzimidazole-based thioamide derivatives were designed, synthesized, and evaluated for their anticancer potential, supported by EGFR-targeted molecular docking studies. The synthetic strategy involved a base-mediated nucleophilic substitution reaction between 1-(substitutedphenyl)-2-((5-(difluoromethoxy)-1H-benzo[d]imidazol-2-yl)thio)ethan-1-one intermediate (1) and brominated nitrobenzyl derivative (2), enabling efficient CC bond formation at the C5 position of the benzimidazole ring. Reaction parameters were systematically optimized, including solvent, base, and temperature, wherein acetonitrile as solvent and potassium carbonate as base under reflux conditions afforded the best yields. Under optimized conditions, a library of ten derivatives was synthesized and fully characterized using NMR spectroscopy. The synthesized compounds were evaluated for in vitro cytotoxic activity against three human cancer cell lines: MCF7 (breast), A-549 (lung), and HEP-G2 (liver). Several derivatives exhibited promising anticancer activity, with compound 6-8b emerging as the most potent, displaying IC₅₀ values of 3.70 μM against A-549 and 5.38 μM against HEP-G2 cells. Molecular docking studies against the T790M-mutated EGFR kinase domain (PDB ID: 2JIV) revealed favorable binding interactions, superior docking scores, and binding energies compared to the reference inhibitor Neratinib. ADME predictions were made using Qikprop. These derivatives may represent a preliminary lead scaffold warranting further mechanistic validation and structural optimization; however, experimental confirmation of EGFR target engagement is required before definitive anticancer claims can be made.