Patent ID: 7939673

Claim:
A process for preparing a 3-dihalomethylpyrazole-4-carboxylic acid derivative of formula (I) in which R 1 is selected from C 1-12 -alkyl radicals, and C 5-18 -aryl or C 7-19 -arylalkyl radicals, Y is selected from (C═O)OR 6 , CN and (C═O)NR 7 R 8 , where R 6 , R 7 and R 8 are each independently selected from C 1-12 -alkyl radicals, and C 5-18 -aryl or C 7-19 -arylalkyl radicals; and X is F, Cl or CF 3 comprising reacting an α-fluoroamine of formula (III) in which R 4 is selected from C 1-12 -alkyl radicals, and C 5-18 -aryl or C 7-19 -arylalkyl radicals, R 5 , independently of R 4 , is selected from C 1-12 -alkyl radicals, C 5-18 -aryl and/or C 7-19 -arylalkyl radicals, and X is F, Cl or CF 3 , in the presence of a Lewis acid (Z) with an acrylic acid derivative of formula (II) in which A is selected from O, S and NR 3 , Y is selected from (C═O)OR 6 , CN and (C═O)NR 7 R 8 , where R 6 , R 7 and R 8 are each independently selected from C 1-12 -alkyl radicals, and C 5-18 -aryl or C 7-19 -arylalkyl radicals; and R 2 and R 3 are each independently selected from C 1-12 -alkyl radicals, C 5-18 -aryl; C 7-19 -aryl-alkyl radicals, —OR′, —SR′, and —NR′ 2 , where R′ may be a (C 1 -C 5 ) alkyl radical, or R 2 and R 3 , together with the nitrogen atom to which they are bonded, may form a five- or six-membered ring, to give a vinamidinium salt of formula (IV) in which Z − is an anion; and subsequent reaction thereof with an alkylhydrazine of formula (V)