Conducting Polyaniline is an Efficient Catalyst for Synthesis of 3,4-dihydropyrimidin-2-(1H)-one Derivative Under Solvent-Free Conditions

A novel effective synthesis of 3,4-dihydropyrimidin-2(1H)-one (DHPM) derivatives, using conducting polyaniline (PANI) as a catalyst from aldehydes, β-ketoester and urea under solvent free conditions has been described. The effect of organic solvents on the human body and the environment is hazardous and its disposal is a major problem. Hence, solvent less organic reaction have attracted attention of chemists. Solvent free solid-state reaction carried out using the reactant alone reduces the pollution, and is more economical and environment friendly. PANI catalyst and solvent free condition reduces the side reactions that occur in other protonated acid media. The use of the sonochemical method is a green route for the synthesis of dihydropyrimidinones (DHPM). Compared with the traditional reaction, this method has the advantage of shorter reaction time with excellent yield, purity of DHPM and low loading of raw materials. Polyaniline is a mild, stable, recyclable, cheaper and highly efficient catalyst and used several times with excellent yield for the dihydropyrimidinone synthesis. Polyaniline (PANI) was characterized by UV-Visible, FTIR, XRD and SEM studies. DHPM were characterized by NMR, MS and IR spectroscopy. In the present paper, a green approach for the synthesis of dihydropyrimidinone assisted by polyaniline as a catalyst under solvent-free conditions is reported.