反应详情

温度

-25 °C

To a solution of 4-nitro-1H-pyrazole (5.0 g, 44.2 mmol) in anhydrous DMF (100 mL) was NaH (60% in oil) (1.94 g, 48.6 mmol) while being stirred at −25° C. under nitrogen. The mixture was stirred for 30 min before bromoethane (5.30 g, 48.6 mmol) was added. The mixture was continued to stir under nitrogen at −25° C. for 6 h. The solution was diluted with ethyl acetate (100 mL), washed with water (2×50 mL) and brine solution (50 mL), dried over magnesium sulfate, and filtered. The filtrate was concentrated under reduced pressure to afford crude 123a (5.0 g, 80%), which was used in next step without further purification. MS-ESI: [M+H]+ 142.0

1. additionwas added
2. stirringto stir under nitrogen at −25° C. for 6 h
3. washwashed with water (2×50 mL) and brine solution (50 mL)
4. dry with materialdried over magnesium sulfate
5. filtrationfiltered
6. concentrationThe filtrate was concentrated under reduced pressure