Catalyst-free, Knoevenagel-Michael Addition Reaction of Dimedone under Microwave Irradiation: An Efficient One-pot Synthesis of Polyhydroquinoline Derivatives

Present investigation reports a concise and efficient protocol for the synthesis of polyhydroquinoline derivatives through coupling of four different components viz. aromatic aldehydes, dimedone, ethyl acetoacetate or ethyl cyanoacetate, and ammonium acetate. The same phenomenon can be observed using arylmethylene bis(3-hydroxy-2-cyclohexene-1-ones), ethyl acetoacetate, and ammonium acetate in one pot under microwave irradiation. The key advantages of the given protocol include short reaction time, high yields, and simple work-up and purification procedure. The present method also allows us to synthesize highly functionalized title compounds from simple and readily available starting materials.