Current Progress in Visible Light-induced Synthesis and Functionalization of N- and S-Heterocycles: A Sustainable Perspective

Heterocycles are of much importance as the majority of the existing drugs contain one or more heterocyclic units in their structures. Among all the heterocycles, nitrogen, and sulphurcontaining ones occupy major space, and they have special properties which make them suitable for the textile, cosmetic, and paint industries other than pharmaceutical. Recently, visible light has emerged as a powerful tool for performing various reactions at ambient temperatures and mild conditions and thus it has been used for the key step in the synthesis of many molecules. In addition, visible light assisted methods are usually cost and time effective. Thus, this review highlighted the recent developments in visible light induced methods for the synthesis of some selected biologically active N- and S- containing heterocycles such as benzothiazoles, indoles and triazoles and their functionalization. The advantages, green aspects and limitations of these methods have also been discussed.