反応 #629352

反応方程式

ethyl oxalate

4-bromopyridine

butyl lithium

→

title product

4-pyridyl glyoxylic acid

溶媒

THF

tetrahydrofuran

THF

反応条件

後処理

1. 1
   workup.DISSOLUTIONdissolved in 120 ml
2. 2
   その他into a stirred 0° C.
3. 3
   workup.STIRRINGThe solution was stirred at 0° C. for 45 minutes
4. 4
   その他quenched by addition of 65 ml
5. 5
   温度This was warmed to room temperature
6. 6
   workup.ADDITIONpoured into 500 ml
7. 7
   抽出extracted with 3×200 ml
8. 8
   洗浄The combined organic layers were washed with brine
9. 9
   乾燥dried over magnesium sulfate
10. 10
    ろ過filtered
11. 11
    濃縮concentrated to a brown oil
12. 12
    その他chromatographed on silica gel
13. 13
    洗浄eluted with 1:2 ethyl acetate hexane
14. 14
    その他A viscous yellow oil was obtained

実験手順

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.

出典