表面活性剂和质子酸协同催化合成3,4-二氢嘧啶-2-酮

Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones Using Protic Acid Surfactant and Synergistic Catalysis

经典的Biginelli反应用盐酸作催化剂，通常收率较低（20％～50%），而表面活性剂和质子酸协同催化能有效的促进Biginelli反应进行。以苯甲醛、β-酮酸酯和尿素三组分为反应物，再加入表面活性剂（β-环糊精）和盐酸，用乙醇作溶剂，缩合制备3，4-二氢嘧啶-2-酮。考察了反应物摩尔比、反应时间、β-环糊精的物质的量和不同表面活性剂等因素对收率的影响。结果表明，在苯甲醛、β-酮酸酯、尿素的摩尔比为1．0：1．2：1．5，β-环糊精的物质的量为2．5mmol，浓盐酸的体积为0．25mL，乙醇的体积为25mL，回流时间为8h的条件下，3，4-二氢嘧啶-2-酮收率达到92％．

The yield of the classical Biginelli reaction is low（20% -50% ） when hydrochloric acid is used as catalyst, but synergistic catalysis of surfactant combined with proton acid could accelerate the Biginelli reaction effectively. 3,4 Dihydropyrimidin- 2（1H） - ones was synthesized under the condition of β-cyclcxtextrin as surfactant combined with hydrochloric acid in ethanol solution, and the condensation substrates were benzaldehyde, β-ketoacid ester and urea, The effects of substrate mole ratio, reaction timc, the amount of β-cyclodextrin and other surfactants on the yields were investigated. The resuhs show that the yield of 3, 4 dihydropyrimidin 2（1H） ones is up to 92%, under the conditions of 1.0： 1.2：1.5 mole ratio of benzaldehyde, β - ketoacid ester and urea, 2.5 mmol β-cyclodextrin, 0.25 mL hydrochloric acid, 25 mL ethanol, and 8 hours refluxing time.