反应详情

A solution of bromine (5.1 g, 32 mmol) in acetic acid (10 mL) was added dropwise to a solution of potassium acetate (3.9 g, 40 mmol) and 1,5-dimethyl-1H-pyrazole-3-carbonitrile in acetic acid (50 mL). Following the addition, the reaction was stirred for 30 minutes. Saturated aqueous sodium hydrogensulfite was added, and the mixture was stirred until it became colorless. The volatiles were removed under reduced pressure, and the residue was stirred with water to form a solid. The solid was isolated by filtration, washed with water, and recrystallized from ethanol and then from hexane to provide 2.5 g of 4-bromo-1,5-dimethyl-1H-pyrazole-3-carbonitrile as colorless needles, mp 92-94° C.

1. additionthe addition
2. stirringthe mixture was stirred until it
3. customThe volatiles were removed under reduced pressure
4. stirringthe residue was stirred with water
5. customto form a solid
6. customThe solid was isolated by filtration
7. washwashed with water
8. customrecrystallized from ethanol