Experimental and Theoretical Investigation of One-pot Synthesis of 2-Amino-4H-chromenes Catalyzed by Basic-functionalized Ionic Liquids

An efficient and environmentally benign procedure for the reactions of three components condensation of salicylaldehyde and two different CH acids to give 2-amino-4H-chromenes catalyzed by a series of basic-functionalized ionic liquids was reported. The most possible reaction pathway was proposed for the first time by performing density functional theory (DFT) calculations. Both cation and anion of [Bmim]OH have a cooperative effect on the reaction. [Bmim]+ increases the electrophilicity of salicylaldehyde via intermolecular hydrogen bonds, while OH− deprives proton of two CH acids to strengthen their nucleophilic ability.