反应详情

温度

90 °C

To a suspension of 2-amino-5-bromo-4,6-dimethylpyridine (4.02 g, 20.0 mmol) in HBF4 (48% in water, 15 mL) cooled in an ice bath was added a solution of NaNO2 (1.73 g, 25.0 mmol) in water (5 mL). The reaction mixture turned clear, and 10 min later a precipitate was formed. The precipitate was collected by filtration, dried under vacuum and added to hot heptane (100 mL) pre-heated at 90° C. After heated at 90° C. for 2 h the mixture was cooled to room temperature and filtered. The filtrate was concentrated under vacuum to afford 3-bromo-2,4-dimethyl-6-fluoropyridine as a pale yellow solid (1.45 g, 36%). 1H NMR (CDCl3): δ 2.43 (s, 3H), 2.61 (s, 3H), 6.66 (d, 1H, J=3.0 Hz). 19F NMR (CDCl3): δ 3.24.

1. temperaturecooled in an ice bath
2. custom10 min later a precipitate was formed
3. filtrationThe precipitate was collected by filtration
4. customdried under vacuum
5. additionadded to hot heptane (100 mL)
6. temperatureAfter heated at 90° C. for 2 h the mixture
7. temperaturewas cooled to room temperature
8. filtrationfiltered
9. concentrationThe filtrate was concentrated under vacuum