A one-pot multicomponent reaction for the synthesis of 2-amino-2-chromenes promoted by N,N-dimethylamino-functionalized basic ionic liquid catalysis under solvent-free condition

A simple, clean, and environmentally benign three-component process to the synthesis of 2-amino-4H-chromenes using N,N-dimethylaminoethylbenzyldimethylammonium chloride, [PhCH2Me2N+CH2CH2NMe2]Cl-, as an efficient catalyst under solvent-free condition is described. A wide range of aromatic aldehydes easily undergo condensations with alpha-naphthol and malononitrile under solvent-free condition to afford the desired products of good purity in excellent yields. Taking into account environmental and economical considerations, the protocol presented here has the merits of environmentally benign, simple operation, convenient work-up and good yields. Furthermore, the catalyst can be easily recovered and reused for at least five cycles without losing its activities.