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.