Highly Efficient Zn(L‐Pro)2 Catalyst for the Synthesis of 2‐Phenyl Benzimidazoles and 2‐Phenyl Benzothiazoles via Aerobic Oxygenation

The synthesis of biologically active 2‐substituted benzimidazoles and benzothiazoles was developed using Zn(L‐Pro)2 as catalyst in ethanol at room temperature in an aerobic oxidative cyclization reaction involving o‐phenylenediamine and 2‐aminothiophenol with various substituted aldehydes. This process offers a quick and eco‐friendly way to synthesize a variety of pharmacologically important benzothiazoles and benzimidazoles. A simple, an efficient and low‐cost Zn(L‐Pro)2 catalyzed synthesis of 2‐phenyl benzimidazoles and 2‐phenyl benzothiazoles via aerobic oxygenation in EtOH at ambient temperature. The methodology offers short reaction times (4‐30 min) and low catalyst loading (5 mol%), affording pharmaceutically significant benzothiazoles and benzimidazoles via one‐pot synthesis.