2,3-二氯苯甲酸的合成新方法

A New Method for Synthesis of 2,3-Dichlorobenzoic Acid

探索了一条合成抗癫痫药拉莫三嗪(Lamotrig-ine)的关键中间体2,3-二氯苯甲酸的新路线.以邻氯苯胺为原料,与水合三氯乙醛、盐酸羟胺反应先制得邻氯基(N-肟基乙酰)苯胺,用浓硫酸关环生成3-氯靛红.再用过氧化氢氧化,制得2-氨基-3-氯苯甲酸;然后再经过酯化、重氮化、Sandmeyer氯代和水解,得到了目标产物2,3-二氯苯甲酸,反应总收率为49%.其结构经1H NMR、13C NMR和IR表征.

This paper provides a novel method for preparation of 2,3 - dichlorobenzoic acid. The cheap available starting material, O - chloroaniline, reacted with trichloroacetaldehyde monohydrate and hydroxylamlne hydrochloride to produe N- （2 - chlorophenyl） - 2 - （hydroxyimino） acetamide; which was treated with concentrated sulfuric acid to obtained 3 - chlorolisatin, then 3 - chlorolisatin was oxidized by hydrogen peroxide to afford 2 - amino - 3 - chlorobenzoic acid. Through other four steps, such as esteritication, diazotizafion, Sandmeyer- chloronati - on and hydrolysis, the target compound 2,3 - dichlorobenzoicacid was obtained in overall yield of 49% with 3 - chlorolisatin as intermediate. It is an important chemical for the synthesis of Lamotrigine. The structure of the target compound was identified by IR ^1H NMR,^13C NMR.