Patent ID: 7906656

Claim:
A process for preparing an iodopyrazolylcarboxylic acid derivative of formula (II) in which R 6 represents C 1 -C 3 -alkyl, C 1 -C 2 -alkoxy-C 1 -C 2 -alkyl, or C 1 -C 3 -haloalkyl having 1 to 7 fluorine, chlorine, and/or bromine atoms, and X 1 represents chlorine or hydroxyl, comprising (i) in a first step reacting a 3-aminopyrazole-4-carboxylic ester of formula (XIV) in which Alk represents C 1 -C 4 -alkyl, and R 6 represents C 1 -C 3 -alkyl, C 1 -C 2 -alkoxy-C 1 -C 2 -alkyl, or C 1 -C 3 -haloalkyl having 1 to 7 fluorine, chlorine, and/or bromine atoms, with an iodinating agent in the presence of isoamyl nitrite to form a 3-iodo-pyrazole-4-carboxylic ester of formula (XV) in which Alk and R 6 are as defined for formula (XIV), and (ii) in a second step hydrolyzing the 3-iodopyrazole-4-carboxylic ester of formula (XV) to the corresponding acid of formula (II) in which X 1 is hydroxyl with a base in the presence of a diluent, and (iii) optionally in a third step, reacting the resultant acid from the second step with a chlorinating agent in the presence of a diluent to give the corresponding acid chloride of formula (II) in which X 1 is chlorine.