I2/NaH/DMF as oxidant trio for the synthesis of tryptanthrin from indigo or isatin

Abstract

Tryptanthrin, a product present in several natural sources used as colorants and very relevant in the field of Medicinal Chemistry, was synthesized from indigo and isatin under mild conditions using microwave irradiation. A plausible mechanism for the synthesis of tryptanthrin using the oxidant system formed by iodine, sodium hydride and DMF, the latter acting with dual activity as solvent and as the oxygen source, is proposed.