The present invention relates to method for the preparation of 3-fluoroalkyl-1-methylpyrazol-4-carboxylic acid, wherein it comprises the following steps: step 1, fluoroacetyl fluoride derivative shown in Formula I undergoes condensation with dimethylamino vinyl methyl ketone, as a result, 3-dimethylamino methylene-fluoro-2,4-pentanedione derivative shown in Formula II is formed; step 2, ring closing reaction takes place between said 3-dimethylamino methylene-fluoro-2,4-pentanedione shown in Formula II and methylhydrazine, in this way, 3-fluoroalkyl-1-methyl-4-acetyl pyrazol derivative shown in Formula III is obtained; step 3, the said 3-fluoroalkyl-1-methyl-4-acetyl pyrazol derivative shown in Formula III is oxidized in the presence of alkali, and then acidified, in this way, 3-fluoroalkyl-1-methylpyrazol-4-carboxylic acid shown in Formula IV is formed. Preparing method of present invention, wherein the required preparing route is simple, the raw material cost is low, the resulting yield of each step is high, and it is suitable for industrialization.
本发明涉及一种制备3-氟烷基-
1-甲基吡唑-4-羧酸的方法,其中包括以下步骤:步骤1,式I所示的
氟乙酰氟衍
生物与二甲基
氨基
乙烯基甲基酮发生缩合反应,从而形成式II所示的3-二甲基
氨基亚甲基-
氟-
2,4-戊二酮衍
生物;步骤2,式II所示的3-二甲基
氨基亚甲基-
氟-
2,4-戊二酮与甲基
肼发生环合反应,得到式III所示的3-氟烷基-1-甲基-4-乙酰
吡唑衍
生物;步骤3,式III所示的3-氟烷基-1-甲基-4-乙酰
吡唑衍
生物在碱的存在下被氧化,然后酸化,从而形成式IV所示的3-氟烷基-
1-甲基吡唑-4-羧酸。本发明的制备方法,所需制备路线简单,原料成本低,每个步骤的产率高,适合工业化生产。