反应详情

3-(2,4-Dichlorophenyl)-5-hydroxy-1-methylpyrazole (1.3 g (5 mmol)) synthesized in Reference Example 6 and 0.3 g (7.5 mmol) of sodium hydroxide were dissolved in 5 mL of ethanol. While stirring the resulting solution at room temperature, 1.0 g (11 mmol) of a 35% formalin solution was added dropwise thereto, followed by stirring at the same temperature for 1 hour. Subsequently, 0.9 g (5 mmol) of sodium p-toluenesulfinate was charged thereto at room temperature, and the obtained mixture was stirred for 2 hours. After the reaction, 2.5 g (25 mmol) of 35% hydrochloric acid was added dropwise thereto, 15 mL of water was further added, and the precipitated crystal was collected by filtration, washed twice with 10 mL of water and dried by a hot air drier to obtain 2.1 g (yield: 90.3%) of the title compound as a pale yellow 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 10 mL of water
6. customdried by a hot air drier