Ultrasound-Mediated Green Synthesis of Imidazo[1,2-a ]pyridines and Imidazo[2,1-b ]thiazoles through C(sp 3 )-H Functionalization

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-butylhydroperoxide catalytic system. The reaction takes place in water, agreen solvent, and does not require a metal catalyst; it also gives goodyields of the products. The method offers numerous noteworthy char-acteristics, 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, andcan be conducted under ambient reaction conditions.