4-氨基-3,5-二氯-2,6-二氟吡啶的合成研究

Synthesis of 4-Amino-3,5-dichloro-2,6-difluoropyridine

以3,5-二氯-2,4,6-三氟吡啶(TFP)为原料,水为溶剂,采用带压氨解合成氟草烟的中间体4-氨基-3,5-二氯-2,6-二氟吡啶,对反应条件进行了研究,优化反应条件为:反应温度80℃,反应时间30min,物料比n(TFP)∶n(氨水)=1∶3.5,苄基三乙基氯化铵的用量为TFP质量的5%。优化反应条件下收率为83.5%,产品含量为98.6%,其结构经红外分析、元素分析、核磁共振确证。

4-Amino-3,5-dichloro-2,6-difluoropyridine, an important intermediate of fluroxypyr, was synthesized from 3,5-dichloro-2,4,6-trifluoropyridine （TFP） via reaction of amination using water as the solvent and under the pressure. The optimum reaction conditions were abtained as follows. Temperature was 80℃, reaction time was 30min, the molar ratio of TFP and aqueous ammonia was 1 ： 3.5, the catalyst （benzyl triethyl ammonium chloride） amount was 5% comparing to TFP （m/m）. The yield and purith was 83.5% and over 98.6%, respectively. The product was confirmed by IR, elementary and ^1H NMR.