Reaktion #629352

Reaktionsgleichung

ethyl oxalate

4-bromopyridine

butyl lithium

→

title product

4-pyridyl glyoxylic acid

Lösungsmittel

THF

tetrahydrofuran

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 65 ml
5. 5
   TemperaturThis was warmed to room temperature
6. 6
   workup.ADDITIONpoured into 500 ml
7. 7
   Extraktionextracted with 3×200 ml
8. 8
   WaschenThe combined organic layers were washed with brine
9. 9
   Trocknendried over magnesium sulfate
10. 10
    Filtrationfiltered
11. 11
    Einengenconcentrated 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

15.0 g. (0.095 mol) of 4-bromopyridine in 7 ml. of dry tetrahydrofuran (THF) was added dropwise at -70° C. to a solution of butyl lithium (1.6 M, 60.9 ml., 0.098 mol) dissolved in 120 ml. of dried THF over a ten minute period. The resulting very deep purple mixture 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 (55.2 g., 0.38 moles) in 90 ml. of dry THF. The solution was stirred at 0° C. for 45 minutes and then quenched by addition of 65 ml. glacial acetic acid. This was warmed to room temperature and poured into 500 ml. of water adjusted to pH 7.0 with saturated sodium bicarbonate and extracted with 3×200 ml. ethyl acetate. The combined organic layers were washed with brine, dried over magnesium sulfate filtered and concentrated to a brown oil. This oil was flash chromatographed on silica gel eluted with 1:2 ethyl acetate hexane. A viscous yellow oil was obtained; 5.8 g (34%), m/e 179, spectral data consistent with structure of title product.

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