A Chitosan N‐ium Acetate Catalyzed Michael‐aldol‐dehydration‐imino‐Diels‐Alder Reaction: One‐pot Synthesis of New Angular Acridine‐fused Heterocycles

A highly efficient domino protocol, Michael-aldol-dehydration-imino-Diels-Alder (MAD-IDA) reaction, that allows the intermediate MAD to combine effectively with the arylamine released from the slow reduction of nitroarene via IDA reaction has been described and several new V-shaped acridine-heterocycles have been synthesized after stirring 2-mercapto-quinoline-carbaldehydes/2-mercapto-pyridine carbaldehyde/2-hydroxy-naphthaldehyde, citral/croton-aldehyde, and NaSH in chitosan N-ium acetate in aqueous ethanol at room temperature. The stereo and regioselectivities of the reaction were confirmed by the 2D NMR experiment and the density functional theory level calculations.