Microwave-assisted synthesis of medicinally relevant indoles

Indoles represent an important structural class in medicinal chemistry with broad spectrum of biological activities. The synthesis of indoles, therefore, has attracted enormous attention from synthetic chemists. Microwave methods for the preparation of indole analogs have been developed to speed up the synthesis, therefore, microwave assisted organic synthesis (MAOS) in controlled conditions is an invaluable technique for medicinal chemistry. In this review, indole forming classical reactions such as Fischer, Madelung, Bischler-Mohlau, Batcho-Leimgruber, Hemetsberger-Knittel, Graebe-Ullmann, Diels-Alder and Wittig type reactions using microwave radiation has been summarized. In addition, metal mediated cyclizations along with solid phase synthesis of indoles have been discussed.