反应详情

To a 3.8:1 isomer mix of 4-(1-methyl-1H-pyrazole-5-yl)pyridine and 4-(1-methyl-1-H-pyrazole-3-yl)pyridine (0.30 g) in 5 mL chloroform cooled in ice, was added a solution of 104 μL bromine in 3 mL chloroform. After 5 h, the mixture was treated with excess saturated aqueous sodium bicarbonate and diluted with dichloromethane. The dichloromethane was washed with 3 portions of saturated aqueous sodium bicarbonate, dried over magnesium sulfate, filtered, and evaporated to yield 0.39 g crude product as a brown oil. The crude product was purified by chromatography, eluting with 15:1 ethyl acetate-methanol. Fractions containing the major component were combined to afford 0.17 g (73% yield) of a colorless oil. 1H NMR (CDCl3) was consistent with the desired structure. LC/MS indicated one major product with a M+1 molecular ion of m/z 240.3 by positive ESI.

1. temperaturecooled in ice
2. washThe dichloromethane was washed with 3 portions of saturated aqueous sodium bicarbonate
3. dry with materialdried over magnesium sulfate
4. filtrationfiltered
5. customevaporated
6. customto yield 0.39 g crude product as a brown oil
7. customThe crude product was purified by chromatography
8. washeluting with 15:1 ethyl acetate-methanol
9. additionFractions containing the major component