Synthetic exploration of nitrogen-containing 5- and 6-membered heterocycles and their fused derivatives

Nitrogen-containing heterocycles have created their own hallmark in the field of organic synthesis, chemical sciences and biological sciences. From the past five years, the recent advances observed in the synthesis of N-containing heterocycles via conventional methods by making use of different reagents, bases and appropriate solvent-systems is a salient prospective of this review. The chemistry behind such syntheses is more impactful when employed with cycloadditions, multicomponent reactions, named-reactions and sustainability approaches will aid for in-depth research in heterocyclic chemistry. The use of microwave and ultrasound techniques also play a key role in making chemistry quick. The C-H activation and direct functionalization of nitrogen-containing heterocycles discussed here is among the hot areas of discussion that provide insights of the heterocyclic molecules. Electrochemical oxidative reactions and biocatalytic utility provide the new methods of synthesis. Altogether, the better understanding of the synthesis of biologically active molecules is more impactful and requisite.