反应详情

5-Hydroxy-1-methyl-3-trifluoromethylpyrazole (1.7 g (10 mmol)) synthesized in Reference Example 1 and 0.6 g (15 mmol) of sodium hydroxide were dissolved in 10 mL of toluene. While stirring the resulting solution at room temperature, 1.7 g of paraformaldehyde was charged thereto, followed by stirring at the same temperature for 24 hours. Furthermore, 1.8 g (10 mmol) of sodium p-toluenesulfinate was charged thereto at room temperature, and the obtained mixture was stirred for 8 hours. After the reaction, 5.0 g (50 mmol) of 35% hydrochloric acid was added dropwise thereto, 30 mL of water was further added, and the precipitated crystal was collected by filtration, washed twice with 5 mL of water and dried by a hot air drier to obtain 3.0 g (yield: 88.2%) of the title compound as a pale yellow crystal. The 1H-NMR spectrum agreed with that of Example 6.

1. stirringby stirring at the same temperature for 24 hours
2. stirringat room temperature, and the obtained mixture was stirred for 8 hours
3. additionwas added dropwise
4. filtrationthe precipitated crystal was collected by filtration
5. washwashed twice with 5 mL of water
6. customdried by a hot air drier