以 2 -戊酮和草酸二乙酯为起始原料 ,经 Claisen缩合、环化、甲基化和皂化等反应制得目标化合物 3-正丙基 - 5 -羧基 - 1 -甲基吡唑 3。文献报道的合成方法为四步法 ,在此基础上加以改进 ,形成了两种新的合成路线 ,即三步法和两步法 ,其收率均高于四步法 ,高出 2 7.0 % The target compound 3 - n - propyl - 5 - carboxy - 1 - methylpyrazole 3 was obtained by the reaction of Claisen condensation, cyclization, methylation and saponification with 2 - pentanone and diethyl oxalate as raw materials . The synthesis method reported in the literature is a four-step method, which is improved on the basis of the above two new synthetic routes, namely three-step method and two-step method, the yield is higher than the four-step method, higher than 2 7.0%