2,6-二氯-5-氟-3-甲酸吡啶的合成

Study on the synthesis of pyridine 2,6-dichloro-5-fluoro-3-carboxylic acid

以氟乙酸乙酯、甲酸乙酯和氰基乙酰胺为原料,在甲醇钠的催化下经环化得到2,6-二羟基-5-氟-3-氰基吡啶,然后经PCl5/POCl3氯化和水解得到了标题化合物,总收率43.7%。

A improved process for the preparation of pyridine 2,6-dichloro-5-fluoro-3-carboxylic acid was described where 2,6-dihydroxy-3-cyanc-5-fluoropyridine was prepared using ethyl formate, ethyl fluoroacetate and cyanoacetamide as the starting materials in the presence of sodium methoxide as the catalyst, then the resulted product was converted in one step using phosphorus oxychloride and phosphorus pentachloride in the presence of triethylamine into 2, 6-dichloro-3-cyano-5-fluoropyridine, which after subsequent acid hydrolysis gave pyridine 2,6-dichloro-5-fluoro-3-carboxylic acid with an overall yield of 43.7% .