Iodopyrazolyl carboxanilides
View Patent ↗This invention relates to novel intermediates used in the preparation of iodopyrazolylcarboxanilides of the formula (I) in which R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and Z are as defined in the disclosure, and to the preparation of such intermediates.
1. 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.