The Synthesis Of4,6-Dichloropyrimidine

4,6-dichloropyrimidine is the important intermediate for synthesis of pyrimidines, it has been widely used in medicine and pesticides with pyrimidine synthesis.In the process of production, pyrimidine compounds exhibit a high biological activity, the development of such compounds have attracted the attention of pharmaceutical and pesticide industry.According to the problem of low yield and high cost and the pollution of producing4,6-dihydroxy pyrimidine which taking dimethyl malonate and formamide as materials,a study was conducted on technology of the synthesis process.The optimization process conditions which obtained from orthogonal experiments and single factor experiments were as follows:the concentration of sodium methoxide was26%,the ratio of molar mass was n(dimethyl malonate):n(formamide):n(sodium methoxide)=3.6:3.0:1.0,reaction temperature was50℃,reaction time was2h.The yield of4,6-dihydroxyl pyrimidine was81.22%.This article involved one kind of4,6-Dichloropyrimidine synthesis method, in the presence of anhydrous triethylamine, phosphorus chloride reaction with4,6-Dihydroxypyrimidine and then vacuum distillation the reaction mixture to remove excess phosphorus chloride, the reaction mixture was then added to t a certain amount of ice water to precipitation of the product and then used the dichloromethane to extract4,6-Dichloropyrimidine. The product yield of this method owned a high purityThis paper also studied the influence of different experimental factors on the yield of the product. It can be drawn through the orthogonal experiment that the best molar mass ratio of the reactants was4,6-Dihydroxypyrimidine:phosphorus chloride: triethylamine=1:3:3. The optimum reaction temperature was80-90℃; the optimum reaction time was1hour. The article also described triethylamine dropping experiments; the study found that the triethylamine optimal dropping was12drops per minute. In order to reduce the response costs and improve product yield, this paper also studied the recovery of phosphorus chloride and applied it to the Experiments, the recovery rate can reach31.3%, and the yield can be increased by2-3%. Through the continuous optimization of reaction conditions, the reaction yield and purity of the product had greatly improved.