反应详情

A mixture of 2-chlorophenylboronic acid (5.0 g), 3-bromopyridine (4.8 g) and tetrakis(triphenylphosphine)palladium(0) (1.0 g) in toluene (47 ml), aqueous 2 M sodium carbonate solution (35 ml) and ethanol (2.4 ml) was heated under reflux for 5.5 h. The reaction mixture was cooled, and the toluene layer was separated. The aqueous layer was extracted with ethyl acetate and the combined organic extracts were dried (MgSO4), filtered, and the filtrate evaporated under reduced pressure to give crude 3-(2-chlorophenyl)pyridine (7.9 g). To a solution of the 3-(2-chlorophenyl)pyridine (7.9 g) in dichloromethane (50 ml) was added iodomethane (3.8 ml) and the mixture was stirred for 15 h. The solvent was evaporated under reduced pressure and the obtained residue was crystallized from ethyl acetate to give a pale-yellow crystal. To a solution of the obtained crystals in methanol (60 ml) was added sodium borohydride (1.7 g) under ice-cooling, and the mixture was stirred at room temperature for 3 h. The mixture was quenched with a saturated aqueous sodium chloride solution. The mixture was extracted with ethyl acetate. The extract was washed with a saturated aqueous sodium chloride solution, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure to give a crude 5-(2-chlorophenyl)-1,2,3,6-tetrahydro-1-methylpyridine (5.9 g).

1. temperaturewas heated
2. temperatureunder reflux for 5.5 h
3. temperatureThe reaction mixture was cooled
4. customthe toluene layer was separated
5. extractionThe aqueous layer was extracted with ethyl acetate
6. dry with materialthe combined organic extracts were dried (MgSO4)
7. filtrationfiltered
8. customthe filtrate evaporated under reduced pressure
9. customto give crude 3-(2-chlorophenyl)pyridine (7.9 g)
10. customThe solvent was evaporated under reduced pressure
11. customthe obtained residue was crystallized from ethyl acetate
12. customto give a pale-yellow crystal
13. temperaturecooling
14. stirringthe mixture was stirred at room temperature for 3 h
15. customThe mixture was quenched with a saturated aqueous sodium chloride solution
16. extractionThe mixture was extracted with ethyl acetate
17. washThe extract was washed with a saturated aqueous sodium chloride solution
18. dry with materialdried over anhydrous magnesium sulfate
19. customThe solvent was evaporated under reduced pressure