反应详情

A solution of 4-bromobenzeneboronic acid (2 g) in absolute ethanol (10 ml) was added slowly to a stirred mixture of 4-bromopyridine hydrochloride (1.96 g) in toluene (10 ml), 2M aqueous sodium carbonate solution (25 ml) and tetrakistriphenylphosphine palladium [0] (345 mg) under an atmosphere of argon. The mixture was heated to reflux and stirred at reflux for 3 hours. The mixture was cooled to ambient temperature and water (50 ml) was added. The resulting mixture was extracted with ethyl acetate (3×20 ml). The ethyl acetate extracts were combined and extracted with 2N aqueous hydrochloric acid. The acidic extract was cooled and basified by the addition of aqueous sodium hydroxide solution to give a pH of 9. The mixture was then extracted with ethyl acetate (5×50 ml). The ethyl acetate extracts were combined, dried (MgSO4) and evaporated to give 4-(pyrid-4-yl)bromobenzene as a solid (0.71 g), m.p. 123°-124° C.; microanalysis, found: C, 56.4; H, 3.4; N, 5.9%; C11H8BrN requires: C, 56.4; H, 3.4; N, 6.0%; m/z 234(M+H).

1. temperatureThe mixture was heated
2. temperatureto reflux
3. temperatureat reflux for 3 hours
4. extractionThe resulting mixture was extracted with ethyl acetate (3×20 ml)
5. extractionextracted with 2N aqueous hydrochloric acid
6. extractionThe acidic extract
7. temperaturewas cooled
8. additionbasified by the addition of aqueous sodium hydroxide solution
9. customto give a pH of 9
10. extractionThe mixture was then extracted with ethyl acetate (5×50 ml)
11. dry with materialdried (MgSO4)
12. customevaporated