4-乙氧基-2,3-二氟苯乙酸的合成及副产物研究

Study on by-products and synthesis of 4-ethoxy-2,3-difluorophenylacetic acid

摘要:

摘要：以4-乙氧基-2,3-二氟苯乙酮为起始原料，经Willgerodt-Kindler反应后，碱解、酸化得到纯度99%以上的液晶中间体4-乙氧基-2,3-二氟苯乙酸，对目标化合物进行了1HNMR、IR和GC-MS表征。条件实验结果表明：当n(4-乙氧基-2,3-二氟苯乙酮)﹕n(硫)﹕n(吗啉)为1：2：4，反应温度为105～115 ℃，反应时间为2 h时，Willgerodt-Kindler反应效果最佳，主产物的质量分数为71.54%，4-乙氧基-2-吗啉-3-氟-苯硫代吗啉酰胺副产物的质量分数为14.60%。根据实验的结果，分析了Willgerodt-Kindler反应过程中副产物的产生原因，并对其结构进行了1HNMR和GC-MS确认。

Abstract:

Abstract：More than 99% purity of liquid crystal intermediate of 4-ethoxy-2,3-difluorophenyl acetic acid was synthesized via alkaline hydrolysis and acidification after Willgerodt-Kindler reaction with 4-ethoxy-2,3-difluoroacetophenone as the starting material. The target compound was characterized by 1HNMR、IR and GC-MS. The results of condition experiments showed the effect of Willgerodt-Kindler reaction was best when the molar ratio of 4-ethoxy-2,3-difluoroacetophenone/sulfur/morpholine was 1:2:4, the reaction temperature was 105～115 ℃ and the reaction time was 2 h.The mass ratio of the main product was 71.54%,the mass ratio of the by-product of 4-ethoxy-2-morpholine-3-fluoro-phenyl thiomorpholine amide was 14.60%.The generation reason of the by-product during Willgerodt-Kindler reaction was proposed according to the results of experiments,and its structure was confirmed by 1HNMR and GC-MS.