Ionic liquid catalyzed three-component synthesis of imidazo[1,2-a]pyridines

Imidazo [1, 2-a] pyridine is one of the most important nitrogen heterocycles, play an important role in contemporary chemical biology and medicinal research. New inventive approaches that make more efficient the synthesis of such important heterocycles are therefore highly desirable. Among different types of multicomponent reaction strategy, a powerful strategy to prepare these imidazo [1, 2-a] pyridine derivatives involve the use of multicomponent reactions of aldehyde, isocyanide and 2-aminopyridine (MCRs) to form a single product. Some advantages of multicomponent reactions such as; non-required isolation of intermediates, atom-economic, simple work-up, safe, environmentally acceptable, and resource-effective, time saving, less waste and being performed in one pot manner made it fascinate considerable courtesy of synthetic organic chemists as an efficient tool especially in the synthesis of bioactive heterocycles [1]. Ionic liquids (ILs), being accepted as environmentally benign media as well as catalyst or dual catalyst–solvents in various transformations. Their remarkable characteristics are low volatility, low vapor pressure, reasonable thermal stability, recycling and reusability [2]. In summary, we presented a new protocol for the synthesis of imidazo [1,2-a]pyrimidine in the three-component reaction condition using acidic ionic liquid as a non-toxic and reusable catalyst, which offers considerable benefits such as simple work-up procedure, short reaction times, safe and clean conditions and recyclability of the acidic IL with eco-friendly approach.