反应详情

A solution of (22) (5.70 g, 29.4 mmol) and 2,5-dibromopyridine (2.32 g, 9.8 mmol) in a mixture of toluene (120 cm3), ethanol (40 cm3) and aqueous sodium carbonate (2 M, 40 cm3) was deoxygenated with argon. Tetrakis(triphenylphosphine)palladium(0) (566 mg, 0.49 mmol) was added, and the solution was deoxygenated with argon again, then heated at reflux for 16 hours. Water (200 cm3) and dichloromethane (200 cm3) were added, and the layers were separated. The aqueous layer was extracted with dichloromethane (3×50 cm3). The combined organic extracts were washed with brine (500 cm3) and dried over magnesium sulfate, and the solvent was removed to leave a black oil. The crude product was purified by column chromatography using dichloromethane: light petroleum (1:1) as eluent, to give (23) as a white solid (3.48 g, 94%).

1. customwas deoxygenated with argon
2. customthe solution was deoxygenated with argon again
3. temperatureheated
4. temperatureat reflux for 16 hours
5. additionWater (200 cm3) and dichloromethane (200 cm3) were added
6. customthe layers were separated
7. extractionThe aqueous layer was extracted with dichloromethane (3×50 cm3)
8. washThe combined organic extracts were washed with brine (500 cm3)
9. dry with materialdried over magnesium sulfate
10. customthe solvent was removed
11. customto leave a black oil
12. customThe crude product was purified by column chromatography