反应详情

Sodium (0.48 g, 20.9 mmol) was dissolved in ethanol (50 ml) under an atmosphere of nitrogen at ambient temperature. 2,6-Dibromopyridine (10.0 g, 41.4 mmol) was added and the solution heated to reflux. After 6 h the cooled reaction mixture was partitioned between diethyl ether (150 ml) and water (100 ml). Diethyl ether extracts were washed with water and saturated brine then dried over magnesium sulphate, filtered and evaporated in vacuo to give a semi-solid. Addition of isohexane, filtration and concentration in vacuo gave a residue that was purified by chromatography on silica gel eluting with 80% dichloromethane-isohexane to give 2-bromo-6-ethoxypyridine (1.7 g) as a colourless liquid: δH (400 MHz, CDCl3) 1.38 (3H, t, J 7), 4.34 (2H, quartet, J 7), 6.65 (1H, d, J 8), 7.02 (1H, d, J 7), 7.40 (1H, dd, J 7 and 8); m/z (ES+) 202/204 (M++H).

1. temperaturethe solution heated to reflux
2. customAfter 6 h the cooled reaction mixture
3. customwas partitioned between diethyl ether (150 ml) and water (100 ml)
4. washDiethyl ether extracts were washed with water and saturated brine
5. dry with materialthen dried over magnesium sulphate
6. filtrationfiltered
7. customevaporated in vacuo
8. customto give a semi-solid
9. customgave a residue that
10. customwas purified by chromatography on silica gel eluting with 80% dichloromethane-isohexane