反应详情

5-Chloro-1,3-dimethyl-4-nitropyrazole (43 g, 0.29 moles) was dissolved in carbon tetrachloride (430 ml), bromine (12 ml) was added and the reaction mixture stirred at reflux for 48 hours whilst illuminating with a 500 W light source. A second portion of bromine (12 ml) was added and the reaction mixture refluxed for a further 48 hours. The reaction mixture was cooled and chromatographed on silica (gradient elution commencing with hexane and increasing the proportion of dichloromethane from 0 to 100%). Fractions containing the product were evaporated yielding the title compound as a white solid. (35 g. 47%)

1. temperatureat reflux for 48 hours
2. customwhilst illuminating with a 500 W light source
3. temperaturethe reaction mixture refluxed for a further 48 hours
4. temperatureThe reaction mixture was cooled
5. customchromatographed on silica (
6. washgradient elution
7. temperatureincreasing the proportion of dichloromethane from 0 to 100%)
8. additionFractions containing the product
9. customwere evaporated