反应详情

67.5 g of a solution (10% molar) of 3-(difluoromethyl)-5-fluoro-1-methyl-1H-pyrazole-4-carbonyl fluoride in tetrahydrothiophene-1,1-dioxide were added dropwise to 400 mL of an aqueous 1N NaOH solution. During the addition, the temperature was kept below 20. After 2 h of stirring at room temperature, the mixture was carefully acidified to pH 2 using concentrated hydrochloric acid. The white precipitate formed was filtered off, washed with water and dried. This gave 6 g of 5-fluoro-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid as a white solid.

1. additionDuring the addition
2. customThe white precipitate formed
3. filtrationwas filtered off
4. washwashed with water
5. customdried