Preparation of neutral ionic liquid [2-Eim] OAc with dual catalytic-solvent system roles for the synthesis of 2-amino-3-cyano-7-hydroxy-4-(aryl)-4H-chromene derivatives

Abstract

A novel ionic liquid namely 2-ethyl imidazolium acetate, [2-Eim] OAc, was synthesized, and characterized by studying its FT-IR, 1H and 13C NMR, UV, thermal gravimetric analysis (TGA), differential thermal analysis (DTA) diagrams, and controlled its pH in aqueous media. The described ionic liquid was used as an efficient, homogeneous and reusable catalyst for the synthesis of a good range of 2-amino-4H-chromene derivatives by one-pot three-component condensation reaction of various aldehydes, malononitrile, and resorcinol under solvent-free conditions. Also, optimization of the reaction conditions was investigated using the response surface methodology (RSM), (Central Composite Design (CCD)). Further, the catalyst could be reused and recovered at least four times without appreciable loss of activity.