Catalysis of the Biginelli reaction by ferric and nickel chloride hexahydrates. One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones

An efficient synthesis of 3.4-dihydropyrimidinones from the aldehyde. beta-keto ester and urea in ethanol. using ferric chloride hexahydrate or nickel chloride hexahydrate as the catalyst, is described. Compared with the classical Biginelli reaction conditions, this new method has the advantage of excellent yields (53-97%) and short reaction time (4-5 hours).