N,N-Dimethylamino-Functionalized Basic Ionic Liquid Catalyzed One-Pot Multicomponent Reaction for the Synthesis of 4H-Benzo[b]pyran Derivatives under Solvent-Free Condition

A simple, clean, and environmentally benign three-component process for the synthesis of 4H-benzo[b]pyran derivatives using basic ionic liquid N,N-dimethylaminoethylbenzyldimethylammonium chloride ([PhCH2Me2N+CH2CH2NMe2]Cl-) as an efficient catalyst under solvent-free condition is described. A wide range of aromatic aldehydes easily undergoes condensation with malononitrile and 5,5-dimethylcyclohexane-1,3-dione (dimedone) 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 workup, and good yields. (C) 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:91-94, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20516