H₄SiW₁₂O₄₀/SiO₂催化合成3,4-二氢嘧啶-2(1H)-酮衍生物

Synthesis of 3,4-Dihydropyrimidin-2(1H)-one Derivatives Using H₄SiW₁₂O₄₀/SiO₂ as Catalyst

采用溶胶凝胶法制备H4SiW12O40/SiO2催化剂,以对羟基苯甲醛与乙酰乙酸乙酯、尿素为原料,催化合成5-乙氧羰基-4-(4-羟基苯基)-6-甲基-3,4-二氢嘧啶-2(1H)-酮。考察了反应物摩尔比、反应温度、催化剂用量、反应时间等对产品收率的影响。实验表明,在n (对羟基苯甲醛):n (乙酰乙酸乙酯):n (尿素) = 1:1.5:1.5,反应时间为60 min,催化剂用量为反应物总质量的2.0 %,反应温度为70℃的优化条件下,5-乙氧羰基-4-(4-羟基苯基)-6-甲基-3,4-二氢嘧啶-2(1H)-酮的收率可达93.1%,且对其他几种3,4-二氢嘧啶-2(1H)-酮的催化合成收率在57.6%~95.1%之间,说明H4SiW12O40/SiO2是合成3,4-二氢嘧啶- 2(1H)-酮的良好催化剂,具有良好的应用前景。催化剂和产品结构分别经IR,XRD,SEM和1H NMR,MS表征。

5-Ethoxycarbonyl-4-(4-hydroxyphenyl)-6-methyl-3,4-dihydropy-rimidine-2(1H)-one was synthe-sized from 4-hydroxybenzaldehyde, ethyl acetoacetate and urea using H4SiW12O40/SiO2 as a novel eco-friendly catalyst prepared by a sol-gel technique. The influences of molar ratio of reactant, reaction temperature, catalyst dosage and reaction time were discussed. The optimum conditions are: molar ratio of 4-hydroxybenzaldehyde to ethyl acetoacetate to urea is 1:1.5:1.5;reaction tem-perature is 70?C;catalyst dosage is equal to 2.0% of feed stocks and the reaction time is 60 min;the yield of the product is 93.1%. And the synthesis of other kinds of 3,4-dihydropyrimidine- 2(1H)-one was also tested, and the yield of the products could reach 57.6% - 95.1%. Experimental results reveal that H4SiW12O40/SiO2 is an excellent catalyst for synthesis of 3,4-dihydropy-rimi- dine-2(1H)-one and has good prospects. The catalyst and synthesis products were characterized by IR, XRD and SEM, and 1H NMR and MS, respectively.