| abstract |
The present invention relates to a compound of formula II and a silane compound of formula R 3 n SiCl (4-n) wherein n is 1, 2 or 3, and substituent R 3 is selected from C 1 -C 8 -alkyl and phenyl Independently selected from each other) under a metal selected from metals of Groups 1, 2, 3, 4, and 12 of the periodic table having a redox potential of less than -0.7 V based on a standard hydrogen electrode (at 25 ° C., 101.325 kPa). React,n n n b) a process for the preparation of difluoromethyl-substituted pyrazol-4-ylcarboxylates of formula I, wherein the reaction mixture from step a) is reacted with a compound of formula III:n n n [Formula I]n n n n n n n n [In the meal,n n n R 1 is C 1 -C 8 -alkyl, C 3 -C 8 -cycloalkyl, C 1 -C 4 -alkoxy-C 1 -C 4 -alkyl and the like;n n n [Formula II]n n n n n n n n [Wherein X is fluorine, chlorine or bromine, R 1 means one of the above definitions, R 4 is C 1 -C 8 -alkyl, C 3 -C 8 -cycloalkyl, C 2 -C 8- Alkenyl, benzyl or phenyl;n n n [Formula III]n n n R 2 HN-NH 2 n n n Wherein R 2 means one of the above definitions. |