反应详情

温度

-70 °C

A solution of n-butyllithium in hexane (16.3 ml, 1.55 molar) was added under nitrogen to a stirred solution of 2-bromo-5-chloropyridine (5 g) in dry diethyl ether (70 ml) at -70° C. over a period of 20 minutes. A solution of dimethylcarbamoylchloride (1.36 g) in dry diethyl ether (25 ml) was then added slowly over a period of 20 minutes. The mixture was stirred for a further 20 minutes at -70° C. and a solution of ammonium chloride (5 g) in water (50 ml) was then added and the solution allowed to warm to room temperature. The ether layer was separated and the aqueous solution extracted with diethyl ether (2×50 ml). The ether extracts were combined, dried over magnesium sulfate and evaporated. The residue was chromatographed on silica, eluting with a mixture of ethyl acetate and petroleum ether b.p. 60°-80° C. (1:9). The relevant fractions were combined and evaporated and the residue triturated with diethyl ether and dried to yield the title compound as a buff colored solid (0.86 g), (27%), m.p. 164°-167° C.

1. temperatureto warm to room temperature
2. customThe ether layer was separated
3. extractionthe aqueous solution extracted with diethyl ether (2×50 ml)
4. dry with materialdried over magnesium sulfate
5. customevaporated
6. customThe residue was chromatographed on silica
7. washeluting with a mixture of ethyl acetate and petroleum ether b.p. 60°-80° C. (1:9)
8. customevaporated
9. customthe residue triturated with diethyl ether
10. customdried