反应详情

温度

55 °C

A mixture of 3,5-dibromo-4-nitropyrazole (2) (25 g, 92 mmol) in DMF (120 ml) was added over 45 minutes to a suspension of NaH (4.0 g, 10 mmol; 60% dispersion in oil, prewashed with hexane) in DMF (200 ml) with stirring and under an inert atmosphere. After stirring for 30 minutes, a solution of 1-bromopropane (13.6 g, 111 mmol) in DMF (40 ml) was added over 10 minutes. The reaction mixture was heated at 50-60° C. for 3 hours (monitored by TLC) and the DMF was then evaporated off under reduced pressure. A mixture of DCM/water (300 ml, 1/5) was added and the organic phase was then extracted with water (2×50 ml). The organic phase was dried over Na2SO4 and the solvent was evaporated off under reduced pressure. The crude reaction product was obtained as a black oil (19.4 g, 70%), which was used without further purification in the amination step.

1. stirringAfter stirring for 30 minutes
2. customthe DMF was then evaporated off under reduced pressure
3. additionA mixture of DCM/water (300 ml, 1/5)
4. additionwas added
5. extractionthe organic phase was then extracted with water (2×50 ml)
6. dry with materialThe organic phase was dried over Na2SO4
7. customthe solvent was evaporated off under reduced pressure
8. customThe crude reaction product