Sustainable and selective synthesis of benzimidazole scaffolds using deep eutectic solvents
M. Shaibuna, K. Hiba, A.M. Shebitha, Muhammed Jeneesh Kariyottu Kuniyil, P.B. Sherly mole, K. Sreekumar
Abstract
In the present article, the catalytic activity of Zr based DESs (DES 1-DES 3) and Ce based DESs (DES 4-DES 7) was compared for the synthesis of benzimidazole derivatives. Among the seven DESs, excellent conversion was observed for DES 1 (formed from ZrOCl2·8H2O and urea at 1:5 ratio). This might be due to the higher acidity and lower viscosity of DES 1 compared to others. The present method was found to be efficient for the synthesis of 2-substituted benzimidazoles with interesting characteristics such as easy preparation of the catalyst, high product yield, simple reaction procedure and the reusability of the catalyst. It is for the first time, a recyclable and selective protocol for the synthesis of benzimidazoles using deep eutectic solvent was reported.