反应详情

5-Hydroxy-1-methyl-3-trifluoromethylpyrazole (8.3 g (50 mmol)) synthesized in Reference Example 1 and 3.0 g (75 mmol) of sodium hydroxide were dissolved in 50 mL of water. While stirring the resulting solution at room temperature, 8.5 g (100 mmol) of a 35% formalin solution was added dropwise thereto, followed by stirring at the same temperature for 1 hour. Furthermore, 9.0 g (50 mmol) of sodium p-toluenesulfinate was charged thereto at room temperature, and the obtained mixture was stirred for 2 hours. After the reaction, 25.0 g (250 mmol) of 35% hydrochloric acid was added dropwise thereto, 100 mL of water was further added, and the precipitated crystal was collected by filtration, washed twice with 20 mL of water and dried by a hot air drier to obtain 14.0 g (yield: 83.8%) of the title compound as a white crystal.

1. stirringby stirring at the same temperature for 1 hour
2. stirringat room temperature, and the obtained mixture was stirred for 2 hours
3. additionwas added dropwise
4. filtrationthe precipitated crystal was collected by filtration
5. washwashed twice with 20 mL of water
6. customdried by a hot air drier