反应详情

To a room temperature solution of 3-bromo-2-methylpyridine (2.60 g, 15.1 mmol) and N-bromosuccinimide (NBS) (2.90 g, 16.3 mmol) in CCl4 is added benzoyl peroxide (150 mg, 1.08 mmol). The mixture is heated at reflux for 7 hours, cooled to room temperature, diluted with saturated aqueous sodium bicarbonate (30 mL) and extracted with ethyl acetate (EtOAc) (3×30 mL). The combined organic layers are washed with brine (3×30 mL), dried over magnesium sulfate, filtered and concentrated. LCMS analysis indicated starting material and the desired product. The residue is dissolved in CCl4 (40 mL) and NBS (1.7 g, 9.6 mmol) and benzoyl peroxide (100 mg, 0.72 mmol) is added, and the mixture is warmed at reflux. After 24 hours, the mixture is cooled to room temperature, diluted with saturated aqueous sodium bicarbonate (30 mL) and extracted with EtOAc (3×30 mL). The combined organic layers are washed with brine (3×30 mL), dried over magnesium sulfate, filtered and concentrated. The residue is purified by silica gel chromatography eluting with a mixture of dichloromethane in hexanes (25:75, then 3:7) to afford 3-bromo-2-bromomethyl-pyridine.

1. temperatureThe mixture is heated
2. temperatureat reflux for 7 hours
3. extractionextracted with ethyl acetate (EtOAc) (3×30 mL)
4. washThe combined organic layers are washed with brine (3×30 mL)
5. dry with materialdried over magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated
8. dissolutionThe residue is dissolved in CCl4 (40 mL)
9. temperaturethe mixture is warmed
10. temperatureat reflux
11. temperaturethe mixture is cooled to room temperature
12. extractionextracted with EtOAc (3×30 mL)
13. washThe combined organic layers are washed with brine (3×30 mL)
14. dry with materialdried over magnesium sulfate
15. filtrationfiltered
16. concentrationconcentrated
17. customThe residue is purified by silica gel chromatography
18. washeluting with a mixture of dichloromethane in hexanes (25:75