嘧啶合成新工艺研究

Study on New Process of Synthesizing Pyrimidine

研究了重要的医药中间体嘧啶的合成工艺,以尿素和丙二酸二乙酯为原料,在甲醇钠催化下合成巴比妥酸,并用三氯氧磷在N,N-二甲基苯胺催化下加氯成2,4,6-三氯嘧啶,将2,4,6-三氯嘧啶以钯碳催化,加氢脱氯得到嘧啶。得出每一步的最佳工艺条件,巴比妥酸合成：配料摩尔比1∶1.1∶1.2（丙二酸二乙酯∶尿素∶甲醇钠）,回流,2 h;2,4,6-三氯嘧啶合成：配料摩尔比5∶1（三氯氧磷∶巴比妥酸）,100~105°C,2 h;嘧啶合成：配料摩尔比5∶1（氧化镁∶2,4,6-三氯嘧啶）,溶剂体积比3∶1（水∶乙醇）,0.1 MPa,14 h,60°C。

The new process of preparing pyrimidine which is widely used as pharmaceutical intermediate was studied. Beginning from theraw material urea and diethyl malonate, barbituric acid was prepared with sodium methoxide as catalyst, then 2, 4, 6-trichloropyrimidine was synthesized by reacting of barbituric acid with phosphorus oxychloride in the presence of N,N-dimethylaniline. The object compound was prepared from 2, 4, 6-trichloropyrimidine by catalytic hydrogenation with palladium-charcoal as catalyst. The optimum reaction conditions for every reaction step were studied. For preparing barbituric acid, the mole ratio of diethyl malonate, urea and sodium methoxide was 1 ： 1.1： 1.2, and the mixture was refluxed 2 hours; for preparing 2,4,6-trichloropyrimidine, the mole ratio of phosphorus oxychloride and barbituric acid was 5 ： 1, and the reaction was run at 100- 105℃ for 2 hours; for preparing pyrimidine, the mole ratio of magnesium oxide and 2,4,6-trichloropyrimidine was 5： 1, the volume ratio of water and ethanol was 3 ： 1 and the reaction was run at 0. 1 MPa and 60℃ for 14 hours.