Gallocyanine as An Efficient Catalyst for Synthesis of Benzimidazoles in Aqueous Ethanol

The benzimidazole derivatives have been obtained catalyzed by gallocyanine. A wide range of aromatic aldehydes easily undergo condensation with substituted o-phenylendiamine under mild conditions to afford the target molecules in excellent yields. The products were obtained in 80-93% yields in 30-80 min. The method has several advantages such as use of green solvent, easy work-up, excellent yield and avoiding use of inconvenient preparation of catalyst. Meanwhile, the catalyst gallocyanine is a kind of inexpensive catalyst, which might be applied to broad green catalytic system.