Role of Microwaves in the Synthesis of Fused Five-Membered Heterocycles with Three N-Heteroatoms

The development of new strategies for the synthesis of small-sized heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in three nitrogen atoms containing fused five-membered heterocyclic compounds synthesis is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of N,N,N-heterocycles. The literature data are summarized based on the type of cycles.