[Cl:1][C:2]1[C:3]([C:12]([OH:14])=O)=[N:4][CH:5]=[C:6]([C:8]([F:11])([F:10])[F:9])[CH:7]=1.S(Cl)([Cl:17])=O>>[Cl:1][C:2]1[C:3]([C:12]([Cl:17])=[O:14])=[N:4][CH:5]=[C:6]([C:8]([F:11])([F:10])[F:9])[CH:7]=189.3 g of 3-chloro-5-trifluoromethyl-2-pyridinecarboxylic acid (Example H3) are slowly heated to reflux temperature together with 60 ml of thionyl chloride and the mixture is then subsequently stirred at this temperature for 4 hours. Thereafter, it is cooled to 25° C. and concentrated to dryness in vacuo. Toluene is added twice more and the mixture is concentrated again to dryness. 94.0 g of the desired product are obtained as a yellow residue.
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