3.5 g (0.037 mole) of propionyl chloride are added dropwise to a solution of 7.3 g (0.02 mole) of 5-amino-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-(1,2,4-triazol-1-yl)-pyrazole and 2 g (0.025 mole) of pyridine in 60 ml of acetonitrile, with stirring, and, when the addition has ended, the mixture is stirred at room temperature for a further 12 to 15 hours. For working up, the reaction batch is poured into water and extracted with methylene chloride, the organic phase is washed with water and dried over sodium sulphate and the solvent is removed in vacuo. The residue is dissolved in 100 ml of ethanol, 10 ml of aqueous ammonia are added, the mixture is heated to 50° C. for 15 minutes and concentrated in vacuo and the residue is triturated with water and dried on clay. 6.8 g (81% of theory) of 1-(2,6-dichloro-4-trifluoromethyl-phenyl)-5-propionylamino-4-(1,2,4-triazol-1-yl)-pyrazole of melting point 167° C. to 169° C. are obtained.
