中文摘要：

以磷酸为催化剂,在无溶剂条件下,通过芳香醛（1）、尿素（2）[或硫脲（3）]和乙酰乙酸乙酯的Biginelli缩合反应,合成了10个二氢嘧啶酮类化合物,其结构经1H NMR和IR表征.最佳反应条件：1 1 mmol,,n（1）∶n（2或3）∶n（乙酰乙酸乙酯）=1.0∶1.1∶1.0,于80℃反应15 min;于130℃反应25 min,产率80％～95％.与传统的Biginelli合成方法相比,该方法反应时间由18 h缩短至40 min,产率由20％～50％提高至80％～95％.

英文摘要：

Ten 3,4-dihydropyrimidine-2 （1H）-ones were synthesized by the solvent-free Biginelli＇ s condensation of aldehyde （ 1 ）, urea （ 2 ） [ or thiourea （ 3 ） ] and ethyl acetoacetate using phosphoric acid as the catalyst. The structure were characterized by 1H NMR and IR. The optimum reaction con- ditions at 80 ℃ for 15 rain and 130℃ for 25 rain were as follows： 1 was 1 mmol, n（1） ： n（2 or 3） ：n（ ethyl acetoacetate） was 1.0 ： 1.1 ： 1.0. The yield was 80% ~ 95% under the optimum reac- tion conditions. The new synthetic method reduces the reaction time from 18 h to 40 min and en- hances the yields from 20% ~ 50% to 80% ~ 95%.