反应详情

温度

50 °C

1-Methyl-3-(trifluoromethyl)-1H-pyrazol-5-ol (9.8 g, 0.059 mole) was added in portions to a mixture of phosphorus oxychloride (9.2 g, 0.060 mole) and N,N-dimethylformamide (10 mL, 0.12 mole) with cooling to control the reaction temperature near 40° C. The mixture was then heated and held at 90°-100° C. for one hour and poured while still warm (50° C.) into a mixture of methanol and water. The pH was adjusted to basic with 10% sodium hydroxide. The aqueous solution was washed with ether, then adjusted to acidic pH with 37% hydrochloric acid, and extracted with a mixture of ether and ethyl acetate. The extracts were dried with magnesium sulfate, filtered and concentrated in vacuo to give 5-hydroxy-1-methyl-3-(trifluoromethyl)-1H-pyrazole-4-carboxaldehyde (9.4 g, 82% yield) which was recrystallized from ethyl acetate/cyclohexane to give a white solid, mp=116°-118° C.

1. temperaturewith cooling
2. customnear 40° C
3. temperatureThe mixture was then heated
4. additionpoured
5. washThe aqueous solution was washed with ether
6. extractionextracted with a mixture of ether and ethyl acetate
7. dry with materialThe extracts were dried with magnesium sulfate
8. filtrationfiltered
9. concentrationconcentrated in vacuo