Visible light promoted C-H functionalization of imidazoheterocycles.

Direct C-H functionalization is very important in the late-stage functionalization of drug molecules. In this context, visible light promoted transformations have emerged as a green strategy for C-H functionalization compared to the conventional strategy. Various methodologies have been developed for the C-H functionalization of different bioactive heterocycles employing this visible light photocatalysis in the presence of either transition metal photocatalysts or organophotoredox catalysts and even in the absence of any photocatalyst. The focus of this review is the demonstration of the efficiency of visible light photocatalysis in the direct C-H functionalizations of pharmacologically active imidazo[1,2-a]pyridines and other related imidazoheterocycles.