反应详情

Part B: Crude 2-hydroxyimino-3-oxo-butyric acid methyl ester (24 gram, ˜0.15 mol) dissolved in a magnetically stirred mixture of acetic acid (293 ml), acetic acid anhydride (110 ml) and Pd/C (4 gram) was hydrogenated for 20 hours at room temperature at 1 atmosphere H2 pressure. After filtration over hyflo, the acetic acid and acetic acid anhydride were removed by concentration in vacuo. The resulting crude mixture was purified by flash chromatography (dichloromethane/methanol=95/5 (v/v)) to give 2-acetylamino-3-oxo-butyric acid methyl ester (16.7 gram, 60% yield) as a white solid. Rf (dichloromethane/methanol=95/5 (v/v))=0.4. 1H-NMR (400 MHz, CDCl3): 2.08 (s, 3H), 2.40 (s, 3H), 3.83 (s, 3H), 5.29 (d, J˜7, 1H), 6.71 (br s, 1H).

1. filtrationAfter filtration over hyflo
2. customthe acetic acid and acetic acid anhydride were removed by concentration in vacuo
3. customThe resulting crude mixture was purified by flash chromatography (dichloromethane/methanol=95/5 (v/v))