[OH-].[Na+].O.C([O:6][C:7]([C:9]1[CH:10]=[N:11][N:12]([C:15]2[CH:20]=[CH:19][C:18]([C:21]([F:24])([F:23])[F:22])=[CH:17][N:16]=2)[C:13]=1[Cl:14])=[O:8])C.Cl>C(O)C>[Cl:14][C:13]1[N:12]([C:15]2[CH:20]=[CH:19][C:18]([C:21]([F:24])([F:23])[F:22])=[CH:17][N:16]=2)[N:11]=[CH:10][C:9]=1[C:7]([OH:8])=[O:6]A mixture of 12N aqueous solution of sodium hydroxide (0.5 ml), water (2 ml) and ethanol (4 ml) was added to 5-chloro-1-[5-(trifluoromethyl)pyridin-2-yl]-1H-pyrazole-4-carboxylic acid ethyl ester (120 mg), and stirred at 80° C. for four hours. After the reaction, 1N hydrochoric acid aqueous solution was added under ice-cooling, the precipitated solid was washed with ethyl acetate to give 5-chloro-1-[5-(trifluoromethyl)pyridin-2-yl]-1H-pyrazole-4-carboxylic acid (50 mg).
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