An Update on the Recent Green Synthetic Approaches for Imidazo[1,2-a] Pyridine: A Privileged Scaffold

Imidazo[1,2-a]pyridine is a fused bicyclic heterocycle that is known as a "drug prejudice" scaffold because of its numerous uses in organic and medicinal chemistry for the development of new drugs. As an outcome, numerous techniques for synthesizing this important class of compounds have been established. Some methods, however, are associated with toxic and corrosive catalysts, longer reaction times, poor yields, lower purity, and byproducts in addition to the desired product. Green synthetic methods, which include microwave- assisted synthesis, catalyst-free, solvent-free, green solvent-based synthesis, mechanochemistry, and many others, are used to reduce the usage and production of harmful organic substances. These techniques improve reaction efficiency compared to conventional ones and also reduce the utilization and production of hazardous chemicals. Due to the implication of the imidazo[1,2-a]pyridine backbone as a biologically active ubiquitous fragment and the current demands of reducing toxic solvents, catalysts, and energy consumption, this review focuses on providing comprehensive highlights of the recent green synthetic pathways for imidazo[1,2-a]pyridine.