2-氯-5-三氯甲基吡啶合成新方法

New Synthetic Method of 2-Chloro-5-trichloromethyl Pyridine

[目的]2-氯-5-三氯甲基吡啶是合成农药的重要中间体,开发出一种合成2-氯-5-三氯甲基吡啶的新方法。[方法]以DL-苹果酸为起始原料,通过环化、酯化、氨化、水解生成6-羟基烟酸,后者在苯基膦酰二氯的催化作用下以五氯化磷氯化得到目标产物。[结果]经优化,氯化收率达87%;反应总收率达45.6%(以DL-苹果酸计)。[结论]该路线反应条件温和、操作简单、路线短、产品及中间体易于分离提纯,具有工业化应用前景。

[Aims] 2-Chloro-5-trichloromethylpyridine is an important insecticide intermediate, this study aims to develop a new method for synthesis of 2-chloro-5-trichloromethylpyridine. [Methods] 6-Hydroxynicotinic acid was obtained from DL-Malic acid as starting material via cyclization, esterification, ammonolysis and hydrolysis. Then it was treated with phosphorus pentachloride under phenylphosphonic dichloride catalysis to give the object product.[Results] The chlorination yield reached 87% under the optimal condition, the total yield was 45.6% based on DL-Malic acid. [Conclusions] The method has advantages of mild reaction condition, simple operation, short routes,all intermediate products are easily purified and identified, which is suitable for industrial production.