Reaktion #629353

Reaktionsgleichung

ethyl oxalate

3-bromopyridine

butyl lithium

→

title product

3-pyridyl glyoxylic acid

Lösungsmittel

THF

THF

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.DISSOLUTIONdissolved in 120 ml
2. 2
   Sonstigeinto a stirred 0° C.
3. 3
   workup.STIRRINGThe solution was stirred at 0° C. for 45 minutes
4. 4
   Sonstigequenched by addition of 50 ml
5. 5
   Temperaturglacial acetic acid, warmed to room temperature
6. 6
   workup.ADDITIONpoured into 500 ml of water
7. 7
   Extraktionextracted with 2×500 ml ethyl acetate
8. 8
   WaschenThe combined organic layers were washed with brine
9. 9
   Trocknendried (MgSO4)
10. 10
    Filtrationfiltered
11. 11
    Einengenconcentrated in vacuo to a brown oil
12. 12
    Sonstigechromatographed on silica gel
13. 13
    Wascheneluted with 1:2 ethyl acetate hexane
14. 14
    SonstigeA viscous yellow oil was obtained

Vorschrift

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.

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