Recyclable Carbon Nitride Nanosheet-Photocatalyzed Aminomethylation of Imidazo[1,2-a]pyridines in Green Solvent

An efficient and eco-friendly carbon nitride nanosheet (NM-g-C₃N₄)-catalyzed decarboxylative coupling reaction of imidazo-fused heterocycles (i.e., imidazo[1,2-a]pyridines, benzo[d]imidazo[2,1-b]thiazole) with N-phenylglycines in dimethyl carbonate (DMC) has been developed. The toxic solvents, external oxidants, and restricted reaction conditions could be effectively avoided in this powerful and sustainable protocol. Remarkably, NM-g-C₃N₄ could be straightforwardly recovered by simple centrifugation and recycled and reused at least 7 times without an obvious decrease in catalytic activity.