反应详情

温度

-50 °C

A. 1.6 M solution of n-butyl lithium (14 ml) was added dropwise to a stirred solution of 1,3-difluorobenzene (2.17 g) in 34 ml dry tetrahydrofuran at -78° C. After 1 hour at -78° C., the solution was warmed to -50° C. and a solution of anhydrous zinc chloride (3.0 g) in 34 ml tetrahydrofuran was added. After a further 30 minutes at -50° C., a solution of 4-bromopyridine (1.62 g) in 10 ml ether was added followed by 1.0 g of tetrakis(triphenylphosphine) palladium. The solution was then allowed to warm slowly to room temperature and it was then heated at 40° C. for 12 hours. The mixture was cooled to room temperature and was first quenched with saturated aqueous ammonium chloride and then extracted with ethyl acetate. The organic extracts were dried and evaporated yielding a yellow crystalline solid. This material was purified by elution on silica gel with ethyl acetate/hexane to give 1.4 g (73% yield) of the required product as a pale yellow solid of m.p. 113°-114° C. NMR (CDCl3, 60 MHZ): 8.65 (m, 2H), 6.8-7.6 (m, 5H).

1. waitAfter a further 30 minutes at -50° C.
2. temperatureto warm slowly to room temperature
3. temperatureit was then heated at 40° C. for 12 hours
4. temperatureThe mixture was cooled to room temperature
5. customwas first quenched with saturated aqueous ammonium chloride
6. extractionextracted with ethyl acetate
7. customThe organic extracts were dried
8. customevaporated
9. customyielding a yellow crystalline solid
10. customThis material was purified by elution on silica gel with ethyl acetate/hexane