Ethyl Bromide → HCID 13007217, compound

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence