Acetic Anhydride → 1-acetyl-1H-indazole-4-methanol

Acetic anhydride (1.68 mL, 17.8 mmol) was added to a suspension of 3-amino-2-methylbenzyl alcohol (0.82 g, 5.98 mmol) in chloroform (25 mL). Potassium acetate was added and the resulting mixture was stirred at room temperature for 3 h, under reflux for 2 h, and then at room temperature overnight. Amyl nitrite (1.82 mL, 13.7 mmol) and 18-crown-6 (79 mg, 0.3 mmol) were added and the pale yellow cloudy mixture was heated at reflux overnight, then allowed to cool to room temperature and stir for 5 h. The reaction mixture was poured into acetic anhydride (5 mL) and stirred at room temperature overnight. Dichloromethane (20 mL) was added and the solution was washed with sodium hydrogen carbonate solution, water, and brine (10 mL each), dried (Na2SO4), filtered, concentrated, and chromatographed (10-40% ethyl acetate/petroleum ether) to give 1-acetyl-1H-indazole-4-methanol, acetate ester (1.19 g, 86%) as a pale yellow solid.

1. temperatureunder reflux for 2 h
2. customat room temperature
3. customovernight
4. temperaturethe pale yellow cloudy mixture was heated
5. temperatureat reflux overnight
6. temperatureto cool to room temperature
7. stirringstir for 5 h
8. stirringstirred at room temperature overnight
9. washthe solution was washed with sodium hydrogen carbonate solution, water, and brine (10 mL each)
10. dry with materialdried (Na2SO4)
11. filtrationfiltered
12. concentrationconcentrated
13. customchromatographed (10-40% ethyl acetate/petroleum ether)

ORD record

ord-8419a6b9d2e242b88be92e8154ec8024

Source dataset

uspto-grants-2009_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07491741B2