N-(2-氯-1-甲氧基乙基)-2,6-二氟苯甲酰胺的合成新方法

Synthesis Process of N-(2-Chloro-1-methoxyethyl)-2,6-difluorobenzamide

[目的]开发乙螨唑中间体N-(2-氯-1-甲氧基乙基)-2,6-二氟苯甲酰胺的合成新方法,降低原料成本。[方法]以2,6-二氟苯甲酰胺为原料,在强酸性离子交换树脂催化作用下与氯乙醛缩二甲醇反应得到目标化合物。[结果]通过反应条件优化,实验确定的最佳反应条件为:以氯乙醛缩二甲醇本体作为反应溶剂,用量为8.0eq,5%离子交换树脂B催化,反应温度与压力为60℃/500mm Hg,经过甲苯与正己烷精制后得到纯品。收率89%,含量97%。[结论]N-(2-氯-1-甲氧基乙基)-2,6-二氟苯甲酰胺的合成新方法条件温和,收率高,后处理简便,有工业应用价值。

[Aims] This paper aims to develop a new synthetic method of intermediate of etoxazole to reduce cost. [Methods] Taking 2,6-difluorbenzamid and dimethylchloroacetal as the starting materials, the condensation product was obtained catalyzed by strong acid cation exchange resin. [Results] With the optimal reaction conditions, the product was synthesized with 8.0eq dimethylchloroacetal as the solvent and under 60 ℃/500mmHg, the amount of rong acid cation exchange resin B catalyst was 5%. After crystallization with tolune and hexane, the purified product （content 97%） was obtained with a yield of 89%. [Conclusions] The reported method has industrial value with some advantages of mild reaction conditions, easy workup, and high yield.