Ultrasound-Mediated Green Synthesis of Imidazo[1,2-a]pyridines and Imidazo[2,1-b]thiazoles through C(sp3)–H Functionalization

Abstract An ultrasound-assisted expedient protocol has been developed for the synthesis of imidazo[1,2-a]pyridines and imidazo[2,1-b]thiazoles by the C–H functionalization of ketones using a KI/tert-butyl hydroperoxide catalytic system. The reaction takes place in water, a green solvent, and does not require a metal catalyst; it also gives good yields of the products. The method offers numerous noteworthy characteristics, including mild reaction conditions, the absence of a base, broad functional-group compatibility, and excellent reaction yields. Moreover, it avoids the use of costly and air-sensitive chemicals, and can be conducted under ambient reaction conditions.