Ethyl Bromide → HCID 13007217, compound

Temperature

70 °C

A mixture of 4-nitro-3,5-dibromopyrazole (2) (20.0 g; 73.8 mmol) in DMF (160 ml) was added over 20 minutes to a suspension of NaH (3.3 g, 82.5 mmol; 60% dispersion in oil, prewashed with hexane) in DMF (160 ml) with stirring and under an inert atmosphere. After stirring for 30 minutes, a solution of bromoethane (19.3 g; 177.1 mmol) in DMF (35 ml) was added over 5 minutes. The reaction mixture was heated to 70° C. for 4 hours and the DMF was then evaporated off under reduced pressure (oil pump) while heating the reaction medium to 80° C. A DCM/water mixture (200 ml, 1/1) was added. The aqueous phase was washed with DCM (100 ml) and the combined organic phases were then washed with water (50 ml). The organic phase was dried over NaSO4 and the solvent was evaporated off under reduced pressure. The crude 3,5-dibromo-1-ethyl-4-nitro-1H-pyrazole (19.6 g, 89%) is obtained in the form of a solid. This product is used without purification in the following step.

1. stirringAfter stirring for 30 minutes
2. customthe DMF was then evaporated off under reduced pressure (oil pump)
3. temperaturewhile heating the reaction medium to 80° C
4. additionA DCM/water mixture (200 ml, 1/1) was added
5. washThe aqueous phase was washed with DCM (100 ml)
6. washthe combined organic phases were then washed with water (50 ml)
7. dry with materialThe organic phase was dried over NaSO4
8. customthe solvent was evaporated off under reduced pressure

ORD record

ord-8cd4474f31f449a6bd2bb53ccc2c9bcb

Source dataset

uspto-grants-2007_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07300469B2