Ultrasound promoted three‐component synthesis of dihydroindeno[1,2‐ b ]pyrrole derivatives

In this work, a one‐pot three‐component reaction of ninhydrin, primary amines, and 1,3‐dicarbonyl compounds was investigated under various conditions to synthesis of diverse derivatives of dihydroindeno[1,2‐b]pyrroles. Catalyst‐free conditions in EtOH under ultrasound irradiation (45% of amplitude) were selected as a novel and efficient method for synthesis of these fused structures. The reactivity of different primary amines was then investigated for steric and electronic effects. Two examples of difunctional structures were also synthesized by using of 1,4‐diaminobenzene under optimum conditions with high yields. The structure of all products was characterized by spectroscopic methods and elemental analysis.