Multicomponent Synthesis of Functionalized Tetrahydroacridinones: Insights into a Mechanistic Route

A mechanistic study of three-component reactions of various aromatic amines with a number of aldehydes and 1,3-diones was achieved. The unprecedented reaction involved a nucleophilic attack of an aromatic amine on the in situ generated Michael adduct intermediate followed by six-electron ring cyclizations. It is contrary to the common belief that advocates involvement of coupling reactions between a Knoevenagel adduct and an aromatic amine to deliver substituted tetrahydroacridinones.