Diethyl Ether → 5-Bromo-2-ethylpyridine

Temperatur

0 °C

A solution of ethylmagnesium bromide in ether (100 ml, 3M, 0.3 mol) was added dropwise to a cold (5° C.) solution of anhydrous zinc chloride (40.9 g, 0.3 mol) in THF (500 ml) under nitrogen. After stirring for one hour at 0° C., tetrakis(triphenylphosphine)-palladium (0) (1.0 g, 0.87 mmol) was added followed by a solution of 2,5-dibromopyridine (50 g, 0.21 mol) in THF (200 ml). The resulting yellow suspension was stirred at room temperature overnight, quenched by the addition of water (200 ml) and then evaporated in vacuo. The residue was treated with a suspension of ethylenediaminetetraacetic acid (200 g) in water (1000 ml) and dichloromethane (500 ml). The organic layer was separated and the aqueous layer again extracted with dichloromethane (500 ml). The combined extracts were dried (MgSO4), solvent evaporated in vacuo, and the residue distilled (123-124° C., 60 mmHg) to give the required product as a colourless oil (28.8 g, 76%).

1. stirringThe resulting yellow suspension was stirred at room temperature overnight
2. customquenched by the addition of water (200 ml)
3. customevaporated in vacuo
4. additionThe residue was treated with a suspension of ethylenediaminetetraacetic acid (200 g) in water (1000 ml) and dichloromethane (500 ml)
5. customThe organic layer was separated
6. extractionthe aqueous layer again extracted with dichloromethane (500 ml)
7. dry with materialThe combined extracts were dried (MgSO4), solvent
8. customevaporated in vacuo
9. distillationthe residue distilled (123-124° C., 60 mmHg)

ORD-Eintrag

ord-6066826c41484cc78574173cd1051802

Quelldatensatz

uspto-grants-2000_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06015825