Novel acidic ionic liquid as a catalyst and solvent for green synthesis of dihydropyrimidine derivatives

A novel acidic ionic liquid (AIL), 3-(2-carboxybenzoyl)-1-methyl-1H-imidazol-3-ium chloride {[Cbmim]Cl}, was synthesized and used as an efficient and green catalyst for the Biginelli reaction under solvent-free conditions. The present study aims to develop an improved synthesis procedure, based on a one-pot Biginelli condensation reaction, by using different aldehydes, ββ-dicarbonyl compounds, and urea or thiourea. This method, in comparison with the classical Biginelli reaction, has several advantages, including high yield, short reaction time and experimental simplicity.