2-乙氧基-4,6-二氟嘧啶的合成

Synthesis of 2-Ethoxy-4,6-difluoropyrimidine

以2-乙氧基-4,6-二羟基嘧啶为起始原料,经过氯化、氟化合成农药中间体2-乙氧基-4,6-二氟嘧啶。详细考察了原材料配比、反应时间、反应温度对反应的影响,获得了反应优化条件:n(三氯氧磷)∶n(2-乙氧基-4,6-二羟基嘧啶)为2.2∶1,n(氟化钾)∶n(2-乙氧基-4,6-二氯嘧啶)为2.5∶1,氯化反应温度75℃～85℃,氯化反应时间3h,氟化反应温度(160±5)℃,氟化反应时间2.5h。产品总收率75%,产品含量98%。

2-Ethoxy-4,6-difluoropyrimidine was synthesized from 2-ethoxy-4, 6-dihydroxypyrimidine via chlorination and fluorination. Effect of reaction time, temperature, and molar ration of materials for synthesis of 2-ethoxy-4,6-difluoropyrimidine was investigated. The best conditions were as follows： molar ration of phosphorus oxychloride, 2-ethoxy-4,6-dihydroxypyrimidine was 2.2：1, molar ration of potassium fluoride, 2-ethoxy-4,6-dichloropyrimidine was 2.5：1, chlorination reaction temperature 80-85 ℃, chlorination reaction time 3 h, fluorination reaction temperature（160 ± 5） ℃, fluorination reaction time 2.5 h. The total yield and purity of 2-ethoxy-4,6-difluoropyrimidine was 75% and 98%, respectively.