Deep eutectic solvent as a green catalyst for the one-pot multicomponent synthesis of 2-substituted benzothiazole derivatives

Abstract

The need for diverse essential chemicals and resources has markedly risen alongside the advancement of civilization. Regrettably, many toxic solvents used in chemical laboratories and industrial settings pose significant risks to the health of researchers and intensify environmental pollution. Deep eutectic solvents (DESs), serving as an alternative to ionic liquids, provide superior environmental benefits and have garnered significant interest in chemical research. DESs have garnered increasing interest in the field of chemistry for their use as catalysts and solvents. Benzothiazole is an organic molecule with a heterocyclic nucleus (thiazole) that possesses a wide range of biological activities. In this study, we established [CholineCl][Imidazole]₂ as an efficient catalyst for the one-pot multicomponent synthesis of 2-substituted benzothiazole derivatives using conventional heating under solvent-free conditions. Its reactivity remains stable with a maximum yield of 78% for 2-phenylbenzo[d]thiazole, and using a solvent that is both environmentally safe and compatible with the reusability of the [CholineCl][Imidazole]₂ catalyst, the reaction time can be effectively decreased.