Triphenylphosphine: An efficient catalyst for the synthesis of 4,6-diphenyl-3,4-dihydropyrimidine-2(1H)-thione under thermal conditions

An efficient and direct procedure for the synthesis of 4,6-diphenyl-3,4-dihydropyrimidine- 2(1H)-thione derivatives by condensation of 1,3-diaryl-2-propen-1-ones (chalcones) and thiourea in ethanol at 65 °C using triphenylphosphine (PPh3) as a catalyst is reported. The method gave good yields of 4,6-diphenyl-3,4-dihydropyrimidine-2(1H)-thione derivatives in short reaction times in comparison with earlier methods. The catalyst is recycled without loss of activity. Using nontoxic and inexpensive materials, simple work-up, short reaction times and high yields of the products are the advantages of this method.