4-氨基-3,5-二氯-2,6-二氟吡啶合成工艺的优化

The Optimizaton of Synthetic Technology of 3,5-Dichloro-2,6-difluoropyridin-4-amine

对以五氯吡啶为起始原料合成4-氨基-3，5-二氯-2，6-二氟吡啶的工艺进行了改进，研究了相关因素对4-氨基-3，5-二氯-2，6-二氟吡啶收率的影响。结果表明，反应中水分对氟交换反应影响很大，无水条件下氟交换反应温度为100～158℃时中间体3，5-二氯-2，4，6-三氟吡啶收率超过80％；无水KF无需预先用烘箱干燥，氟化产物无需用精馏塔分离，且氨化反应无需耐高温高压设备（室温即可反应），产物总收率为70．4％。此方法操作简单、反应条件温和、设备投资少、生产成本低，具有较高的实用价值。

The synthetic technology of 3,5-dichloro-2,6-difluoropyridin-4-amine with pentachloropyridine as raw material was improved, and the effects of influential factors on yield of 3,5-dichloro-2,6-difluoropyridin- 4-amine were studied. Under anhydrous fluorination reaction condition and fluorination reaction temperature of 100-158℃, the yield of the intermediate 3,5-dichloro-2,4,6：trifluoropyridine was over 80%, and the total yield of the product was 70.4%. It＇s unnecessary to dry undydrous KF in baking oven or to seperate the fluorinated product by fractionating tower. Furthurmore, the ammoniation reaction occured at room temperature, so the apparatus bearing high temperature and pressure were not required. The improved technology, which had simple operation, mild reaction condition, small investment and low cost,was proved to possess high application prospect.