The present invention relates to a process for preparing 2-(aminomethylidene)-4,4-dihalo-3-oxobutyric esters of the formula (I),
wherein R1, R2, R3 are C1-C6-alkyl, C1-C6-haloalkyl, C2-C6-alkenyl, C3-C10-cycloalkyl or benzyl, and/or R2 together with R3 and the nitrogen atom to which the two radicals are attached are a heterocyclic radical, in which a corresponding 3-aminoacrylic ester is reacted with a halogen-substituted acetyl fluoride in the presence of at least one alkali or alkaline earth metal fluoride; and the further conversion of halogen-substituted 2-(aminomethylidene)-3-oxobutyric esters of the formula (I) to halomethyl-substituted pyrazol-4-ylcarboxylic acids and their esters.
本发明涉及一种制备式(I)的2-(
氨甲亚基)-4,4-二卤-
3-氧代丁酸酯的方法,其中R1、R2、R3为C1-C6烷基、C1-C6卤代烷基、C2-C6烯基、C3-C10环烷基或苄基,和/或R2与R3以及它们所连接的氮原子是杂环基,其中相应的3-
氨基
丙烯酸酯在至少一种碱
金属或碱土
金属
氟化物的存在下与卤代乙酰
氟反应;以及将卤代2-(
氨甲亚基)-
3-氧代丁酸酯式(I)进一步转化为卤代甲基取代的
吡唑-4-基
羧酸和它们的酯。