Environmentally Benign Synthesis of Five-Membered 1,3-N,N-Heterocycles by Microwave Irradiation

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 the synthesis of five-membered heterocyclic compounds containing two nitrogen atoms is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of five-membered 1,3-N,N-heterocycles.