反应详情

温度

82.5 °C

5-Chloro-1-cyclohexyl-1H-pyrazole-4-carboxylic acid ethyl ester (1.969 g, 7.67 mmol) was dissolved in methanol (11.5 mL). Lithium hydroxide (0.250 g; 10.44 mmol) and water (11.5 mL) were added. The mixture was heated at 80-85° C. for 1.5 hours, cooled to room temperature and concentrated in vacuo to remove the methanol. The residue was diluted with tetrahydrofuran and concentrated again to ensure complete removal of the methanol. This residue was then diluted with water and acidified with 6N HCl (1.80 mL) to pH 2-2.5. The solid which precipitated out of solution was collected by filtration, washed with water and dried under reduced pressure at 100° C. to give 5-chloro-1-cyclohexyl-1H-pyrazole-4-carboxylic acid (1.676 g, 96%) which was used without further purification. Mass spectrum: m/z: 229.0 (M+H)

1. temperaturecooled to room temperature
2. concentrationconcentrated in vacuo
3. customto remove the methanol
4. additionThe residue was diluted with tetrahydrofuran
5. concentrationconcentrated again
6. customremoval of the methanol
7. additionThis residue was then diluted with water
8. customThe solid which precipitated out of solution
9. filtrationwas collected by filtration
10. washwashed with water
11. customdried under reduced pressure at 100° C.