反应详情

温度

50 °C

To a mixture of 4-amino-1H-pyrazole-3-carboxylic acid methyl ester (50.0 g, 355 mmol) in dioxane (500 mL) was added 2M aqueous NaOH solution (213 mL, 426 mmol), the mixture heated to 50° C. and stirred for 5 h. To this mixture was then added (BOC)2O (81.4 g, 373 mmol), using a dioxane rinse (100 mL) and the mixture heated at 50° C. for a further 5 h, then stirred at ambient for 14 h. The dioxane was removed in vacuo and water (1 L) added. The mixture was taken to pH˜2 using conc. aqueous HCl solution and the solid formed collected by filtration and dried on the filter. The solid was dried further through azeotrope with toluene (×3) and in the vacuum oven to give 4-tert-butoxycarbonylamino-1H-pyrazole-3-carboxylic acid (70.0 g, 87%) as a violet solid.

1. washrinse (100 mL)
2. temperaturethe mixture heated at 50° C. for a further 5 h
3. stirringstirred at ambient for 14 h
4. customThe dioxane was removed in vacuo and water (1 L)
5. additionadded
6. customthe solid formed
7. filtrationcollected by filtration
8. customdried on the filter
9. dry with materialThe solid was dried further through azeotrope with toluene (×3) and in the vacuum oven