反应详情

10.6 g of 5-amino-1-{2-fluoro-4-methyl-5-(2,2,2-trifluoroethylthio)phenyl}-3-hydroxypyrazole was dissolved in 200 mL of toluene, and to this solution, 20.0 g of acetyl chloride was added, followed by reflux with heating for 12 hours. After cooling to room temperature, the solvent was distilled off under reduced pressure, and the obtained residue was purified by column chromatography (developing solvent ethyl acetate:hexane=1:4) to obtain 9.4 g of 3-acetoxy-5-(N,N-diacetylamino)-1-{2-fluoro-4-methyl-5-(2,2,2-trifluoroethylthio)phenyl}pyrazole. Then, 9.4 g of the obtained 3-acetoxy-5-(N,N-diacetylamino)-1-{2-fluoro-4-methyl-5-(2,2,2-trifluoroethylthio)phenyl}pyrazole was dissolved in 100 mL of ethanol, and 10 mL of a 25 mass % ammonia water was added, followed by stirring at room temperature for 30minutes. Then, the solvent was distilled off under reduced pressure, and the obtained solid was washed with diisopropyl ether to obtain 7.0 g of 5-acetylamino-1-{2-fluoro-4-methyl-5-(2,2,2-trifluoroethylthio)phenyl}-3-hydroxypyrazole in the form of white crystals (melting point: 223-225° C.).

1. distillationThen, the solvent was distilled off under reduced pressure
2. washthe obtained solid was washed with diisopropyl ether