反应详情

温度

-78 °C

Potassium thiocyanate (1.45 g, 14.9 mmol) was dissolved in 20 ml of dry methanol, and then a methanol (5 ml) solution of bromine (0.28 ml, 5.44 mmol) was added dropwise with stirring at −78° C. over 8 minutes (inner temperature: not higher than −65° C.). After the completion of adding dropwise, the mixture was stirred at −78° C. for 10 minutes and a methanol (15 ml) solution of 5-amino-1-(2,6-dichloro-4-trifluoromethylphenyl)-3-(1,2,4-oxadiazol-3-yl)pyrazole (1.80 g, 4.94 mmol) was added dropwise over 15 minutes. The solution was stirred at −78° C. for 2 hours, warmed to room temperature and then stirred at the same temperature for 2 hours. The reaction mixture was poured into 100 ml of iced water. After stirring for 30 minutes, the deposited crystal was filtered. The resulting crystal was washed with water and then dried under reduced pressure to obtain 2.04 g (4.85 mmol) of the title compound as a colorless crystal. Yield 98.0%.

1. customhigher than −65° C.
2. additionAfter the completion of adding dropwise
3. stirringthe mixture was stirred at −78° C. for 10 minutes
4. stirringThe solution was stirred at −78° C. for 2 hours
5. temperaturewarmed to room temperature
6. stirringstirred at the same temperature for 2 hours
7. stirringAfter stirring for 30 minutes
8. filtrationthe deposited crystal was filtered
9. washThe resulting crystal was washed with water
10. customdried under reduced pressure