反应详情

温度

80 °C

5-Chloro-1-cyclopentyl-1H-pyrazole-4-carboxylic acid ethyl ester (0.710 g, 2.93 mmol) was dissolved in methanol (4.3 mL). Water (4.3 mL) and lithium hydroxide (0.097 g, 4.05 mmol) were added and the mixture was heated at 80° C. for 2 hours. After cooling to room temperature, methanol was removed in vacuo. Tetrahydrofuran was added to the residue and then removed in vacuo to ensure complete removal of the methanol. The residue was diluted with water and treated with 6N HCl to pH 2-3, resulting in precipitation of a milky solid. The solid was collected, washed with water and dried under house vacuum at 45° C., yielding 5-chloro-1-cyclopentyl-1H-pyrazole-4-carboxylic acid (0.580 g, 91%). This material was used as is without any further purification.

1. temperatureAfter cooling to room temperature
2. custommethanol was removed in vacuo
3. additionTetrahydrofuran was added to the residue
4. customremoved in vacuo
5. customremoval of the methanol
6. additionThe residue was diluted with water
7. additiontreated with 6N HCl to pH 2-3
8. customresulting in precipitation of a milky solid
9. customThe solid was collected
10. washwashed with water
11. customdried under house vacuum at 45° C.