反应详情

To a solution of 1-tert-butyl-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester (5 g, 21.2 mmol, purchased from Bionet) in CH3OH (45 mL) and water (45 mL) was added LiOH (0.54 g, 22.5 mmol). The reaction mixture was stirred at reflux for 4 h, and then the solution was concentrated under reduced pressure to remove the methanol. The residue was diluted with water and the solution was acidified to pH 2 with concentrated HCl. The resulting mixture was then extracted with ethyl acetate three times. The combined organic extracts were concentrated in vacuo to give 1-tert-butyl-5-trifluoromethyl-1H-pyrazole-4-carboxylic acid (4.02 g, 80%), which was used without further purification.

1. temperatureat reflux for 4 h
2. concentrationthe solution was concentrated under reduced pressure
3. customto remove the methanol
4. additionThe residue was diluted with water
5. extractionThe resulting mixture was then extracted with ethyl acetate three times
6. concentrationThe combined organic extracts were concentrated in vacuo