反应详情

温度

-78 °C

To a −78° C. solution of 5-bromo-3-ethyl-1H-indazole (5 g, 22 mmol) in diethyl ether (150 mL) was added t-BuLi (4.84 g, 75.6 mmol). The mixture was stirred at −78° C. for 1 hour. Dry CO2 gas was passed through the reaction mixture at −78° C. for 1 hour and the temperature was slowly raised to room temperature for 2 hours. The reaction mixture was stirred at room temperature for 1 hour and quenched with saturated NH4Cl solution. The ether layer was separated and concentrated to recover unreacted starting material. The pH of the aqueous layer was made acidic with 2 N HCl, which was filtered to afford the title compound (2 g, 47%) as a pale brown solid. 1H NMR (DMSO-d6): δ12.6-13.0 (br, 2H), 8.4 (s, 1H), 7.9 (d, 1H), 7.5 (d, 1H), 3.0 (q, 2H), 1.4 (t, 3H).

1. temperaturethe temperature was slowly raised to room temperature for 2 hours
2. stirringThe reaction mixture was stirred at room temperature for 1 hour
3. customquenched with saturated NH4Cl solution
4. customThe ether layer was separated
5. concentrationconcentrated
6. customto recover unreacted
7. filtrationwas filtered