反应详情

温度

-20 °C

Bromine (4 g) is added, with stirring over 10 minutes, to a mixture of 4-amino-2,6-lutidine (22, 1 g, approximately 6.5 mmol) in 48% HBr (12 ml) at −10° C., followed by cooling to −20° C. A solution of sodium nitrite (1.4 g) in water (4 ml) is added slowly. The mixture is stirred at −20° C. for 1 hour, and then warmed and left at room temperature for 3 hours. The mixture is distilled. The oil fraction of the distillate is extracted with chloroform (3×10 ml). The combined extracts are dried over magnesium sulfate. After filtration, the filtrate is neutralized in an ice-bath using 2M butyl lithium in hexanes until the pH reaches 7. A large amount of salt forms. After filtration, the filtrate is concentrated and dried, yielding 4-bromo-2,6-lutidine (23) oil. 1H NMR (300 MHz, CDCl3) δ 2.82 (s, 6H), 7.5 (s, 2H). MS, m/z 186 and 188 (M+1).

1. temperaturewarmed
2. waitleft at room temperature for 3 hours
3. distillationThe mixture is distilled
4. extractionThe oil fraction of the distillate is extracted with chloroform (3×10 ml)
5. dry with materialThe combined extracts are dried over magnesium sulfate
6. filtrationAfter filtration
7. customthe filtrate is neutralized in an ice-bath
8. filtrationAfter filtration
9. concentrationthe filtrate is concentrated
10. customdried