反应详情

温度

-70 °C

10 g. (0.063 mol) of 3-bromopyridine in 80 ml. of dry THF was added dropwise to a -70° C. solution of butyl lithium (1.6M, 40.6 ml, 0.065 mol) dissolved in 120 ml. of dried THF over a 20 minute period. The resulting brown solution was stirred at -70° C. for 30 minutes and then transferred by nylon tubing under positive nitrogen pressure into a stirred 0° C. solution of ethyl oxalate (36.8 g, 0.25 mol) in 60 ml of dry THF. The solution was stirred at 0° C. for 45 minutes, quenched by addition of 50 ml. glacial acetic acid, warmed to room temperature and poured into 500 ml of water, adjusted to pH 7.0 with 750 ml saturated sodium bicarbonate and extracted with 2×500 ml ethyl acetate. The combined organic layers were washed with brine, dried (MgSO4), filtered and concentrated in vacuo to a brown oil; 24.7 g. This oil was flash chromatographed on silica gel eluted with 1:2 ethyl acetate hexane. A viscous yellow oil was obtained; 1.56 g, m/e 179, spectral data consistent with structure of title product.

1. dissolutiondissolved in 120 ml
2. custominto a stirred 0° C.
3. stirringThe solution was stirred at 0° C. for 45 minutes
4. customquenched by addition of 50 ml
5. temperatureglacial acetic acid, warmed to room temperature
6. additionpoured into 500 ml of water
7. extractionextracted with 2×500 ml ethyl acetate
8. washThe combined organic layers were washed with brine
9. dry with materialdried (MgSO4)
10. filtrationfiltered
11. concentrationconcentrated in vacuo to a brown oil
12. customchromatographed on silica gel
13. washeluted with 1:2 ethyl acetate hexane
14. customA viscous yellow oil was obtained