Convenient and green synthesis of novel 1,2,5-trisubstituted benzimidazole compounds and their antibacterial activity evaluation

An efficient synthesis of 1,2,5-trisubstituted benzimidazoles was explored under microwave irradiation. Twenty novel 1,2,5-trisubstituted benzimidazoles were prepared using K2CO3 as an acid-binging agent starting from 2-substituted benzimidazoles and 4-substituted benzyl chloride. This method revealed broad substrate adaptability and provided the target products in moderate to excellent yield within 15 min. The effect of different substituents on the yield was investigated under the obtained optimal reaction conditions. Besides, the crystal structure of compound 4c in the orthorhombic space group P 2ac 2ab was presented. Also, the antibacterial activity of the synthesized compounds against Mycobacterium smegmatis in vitro at the cellular level was evaluated using rifampicin as a positive control. Product 4s had the best antibacterial activity among the synthesized compounds and was superior to rifampicin.

Automated summary

An efficient synthesis of 1,2,5-trisubstituted benzimidazoles was achieved using microwave irradiation and K2CO3. Twenty novel compounds were prepared in moderate to excellent yield within 15 minutes. The reaction showed broad substrate adaptability, and the effect of different substituents on the yield was investigated. The synthesized compounds exhibited significant antibacterial activity against Mycobacterium smegmatis, with compound 4s showing the best activity surpassing rifampicin.