Designing, Synthesis and Characterization of 2,2- Substituted Benzimidazole Derivatives

Benzimidazole is a privileged heterocyclic scaffold known for its diverse pharmacological activities and wide applications in medicinal chemistry. The present study focused on the designing, synthesis, and characterization of 2,2-substituted benzimidazole derivatives. Six novel compounds (RY-1 to RY-6) were successfully synthesized via an efficient, eco-friendly one-pot condensation of o-phenylenediamine with various substituted benzaldehydes using sodium metabisulfite in ethanol. The synthesized derivatives include RY-1 [2-(4-fluorophenyl)-1H-benzo[d]imidazole], RY-2 [2-(4-chlorophenyl)-1H-benzo[d]imidazole], RY-3 [2-(4-bromophenyl)-1H-benzo[d]imidazole], RY-4 [2-(4-methylphenyl)-1H-benzo[d]imidazole], RY-5 [2-(4-methoxyphenyl)-1H-benzo[d]imidazole], and RY-6 [2-(3,4-dichlorophenyl)-1H-benzo[d]imidazole]. All compounds were obtained in good to excellent yields (75–88%) as crystalline solids and were thoroughly characterized by melting point, FT-IR, ¹H-NMR, ¹³C-NMR, and ESI-MS spectral analysis. The spectroscopic data confirmed the successful formation of the benzimidazole ring system. The green synthetic protocol employed offers advantages such as short reaction time, simple work-up, and avoidance of hazardous reagents, making it suitable for pharmaceutical applications. This work provides a series of well-characterized novel 2-substituted benzimidazole derivatives that can serve as promising leads for further biological evaluation against antimicrobial, anticancer, and other therapeutic targets.