The one-pot synthesis of 4-phenyl-6-methyl-5-ethoxycarbonyl-3,4-dihydropyrimidin-2(H)-one using H_3PW_(12)O_(40)/SiO_2 as catalyst

Objective—To synthesize 4-phenyl-6-methyl-5-ethoxycarbonyl-3,4-dihydropyrimidin-2(H)-one.Methods—The target compound was synthesized via one-pot reaction with ethyl acetoacetate,benzaldehyde and urea as raw materials,H3PW12O40/SiO2 as catalyst and anhydrous ethanol as solvent.The 3,4-dihydropyrimidin-2(H)-one were characterized by melting point measurements,IR,1 HNMR and MS spectroscopy.Results—The influence factors of reaction conditions on the yield of the target compound were discussed and the experiment showed that the best reaction were as follows:under the condition of fixed benzaldehyde consumption is 0.04 mol,the anhydrous ethanol is 15 mL,the mass fraction of the catalyst to reactants is 2.0%,n(benzaldehyde)∶n(ethyl acetoacetate)∶n(urea)is 1∶1.5∶1.5,the reaction time is 90 min,and when the reaction temperature is 90℃,the yield of the product can reach 79.2%.Conclusion—The results indicate that the H3PW12O40/SiO2,which was synthesized by a sol-gel technique,is a novel,effective and reusable catalyst for synthesizing 4-phenyl-6-methyl-5-ethoxycarbonyl-3,4-dihydropyrimidin-2(H)-one.The high activity and stability of the catalyst is well retained after 5 runs.