Process for the preparation of pyrazole carboxylic acid amides

Abstract

The invention relates to a process for the preparation of the fungicide 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid (9-dichloromethylene-1,2,3,4-tetrahydro-1,4-methanonaphthalen-5-yl)-amide of Formula I in high yields and good quality in an economically advantageous way, which process comprises a) reacting the compound II with cyclopentadiene to b) reacting this compound in the presence of an oxidant to the compound of formula IV c) hydrogenating this compound in the presence of a metal catalyst and an inert solvent under hydrogen atmosphere to the compound of formula V d) reacting this compound in the presence of a Bronsted acid followed by a reducing agent to the compound of formula VI e) reacting VI with a compound VII in the presence of a base to a compound of formula VIII f) converting the compound of formula VIII in the presence of an oxidising agent to the compound of formula IX and g) reacting the compound of formula IX in the presence of triphenylphosphane / carbon tetrachloride or triphenylphosphane / bromotrichloromethane to the compound of formula I.