Process for preparing N-substituted 1H-pyrazole-5-carboxylic acid compounds and derivatives thereof

The present invention relates to a process for preparing N-substituted 1 H-pyrazole-5-carboxylic acid compounds of the formula l-A and derivatives thereof, in particular the corresponding carbonylchloride compounds (acid chlorides). It also relates to the use of these acid chlorides for preparing anthranilamide derivatives that are useful pesticides. in which the variables are as defined in the claims and the specification comprising the steps of i) reacting a compound of the formula (II) with a base selected from combinations of a magnesium-organic compound having a carbon bound magnesium and a secondary amine and magnesium amides of secondary amines in the presence of a lithium halide, where the base is used in an amount sufficient to achieve at least 80 % deprotonation of the compound of formula (II); and subjecting the product obtained in step (i) to a carboxylation by reacting it with carbon dioxide or a carbon dioxide equivalent, to obtain a magnesium salt of the compound of formula (l-A) and optionally aqueous workup to obtain the compound of the formula (l-A) as a free acid.