One –Pot Synthesis of Polyhydroquinoline Derivatives via Hantzsch Condensation Reaction Using Nanosized Magnesium Oxide as Heterogeneous Catalyst

Abstract

An efficient, recyclable and environmental-friendly synthetic route to polyhdroquinoline derivatives have been developed via multi-component one-pot Hantzsch reaction of various aromatic aldehyde, 2 equivalents of 5,5-dimethyl-1,3-cyclohexanedione (dimedone), ethyl acetoacetate and ammonium acetate using nano magnesium oxide as a catalyst in ethanol under reflux condition. Reaction with 4-chlorobenzaldehyde was selected as the model reaction and different conditions for temperature, amount of catalyst and kind of solvent have been studied on it. It was found that 0.03 g catalyst in reflux condition and ethanol as solvent is the optimum condition which resulted in 94% yield. The present approach offers several advantages such as short reaction times, easy isolation and purification of product, and safe, non-toxic, recyclable and economic use of catalyst.