반응 #430605

반응 방정식

sodium hydroxide

2,5-dibromopyridine

triethylboron

sodium hydroxide

hydrogen peroxide

→

title compound

수율 90.0%

5-Bromo-2-ethylpyridine

수율 90.0%

용매

THF

THF

반응 조건

후처리

1. 1
   온도The reaction was slowly heated to
2. 2
   온도a very slight reflux for 3 hours
3. 3
   온도It was then cooled down to 0°
4. 4
   추출The mixture was extracted with ether
5. 5
   세척the ether extracts washed with sodium hydroxide, water, brine
6. 6
   건조dried over MgSO4
7. 7
   농축The ether solution was then concentrated
8. 8
   workup.DISTILLATIONthe brown residue was distilled under vacuum (40° C., 1 Torr)

실험 절차

280 mL of 5N sodium hydroxide (1.4 mol, 2.09 eq) was added to a solution of 158 g of 2,5-dibromopyridine (0.67 mol, 1 eq) in 1.4 L of THF. To the resulting solution, 700 mL of 1N triethylboron in THF (0.70 mol, 1.04 eq), 195 mg of bis(acetonitrile)palladium(II) chloride (0.75 mmol, 0.0011 eq) and 414 mg 1,1'-bis(diphenylphosphino)ferrocene (0.75 mmol, 0.0011 eq) were added. The reaction was slowly heated to a very slight reflux for 3 hours. It was then cooled down to 0° and treated sequentially with 140 mL of 5N sodium hydroxide (0.70 mol, 1.04 eq) and 53 mL of 30% hydrogen peroxide (0.70 mol, 1.05 eq) at such a rate that the temperature never exceeded 10° C. The mixture was extracted with ether, and the ether extracts washed with sodium hydroxide, water, brine and dried over MgSO4. The ether solution was then concentrated and the brown residue was distilled under vacuum (40° C., 1 Torr) to give 112 g of the title compound as a clear oil slightly contaminated with the starting material and 2,5-diethylpyridine. Yield ~90%. The 1H NMR is comparable to that reported by J. W. Tilley and S. Zawoiski; J. Org. Chem., 1988,53, 386-390. The material is suitable for use in the next step without further purification.

출처