Single step incorporation of isatin to enaminone: a recyclable catalyst towards assembly of diverse four ring fused pyrrolo[2,3,4-kl]acridin-1-ones

Abstract

A series of pyrrolo[2,3,4-kl]acridin-1-one derivatives were successfully synthesized from facile materials (enaminone and isatin) using a reusable solid acid as catalyst in water. A variety of structurally diverse enaminones and various isatins bearing different functional groups tolerated the reaction and gave the corresponding goal products with good to excellent yields. Advantages of this strategy include the mild conditions, operational simplicity, being convenient and environmentally benign, and the reusability of the heterogeneous catalyst. A mechanism was proposed to explain the formation of different substituted pyrrolo[2,3,4-kl]acridin-1-one derivatives.