反应详情

To a solution of ethyl 2-(1-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yl)-3-oxobutanoate (2.5 g, 8.8 mmol) in ethanol (50 mL) was added ammonium chloride (0.5 g, 9 mmol) in water (5 mL) at room temperature. The mixture was stirred and heated to reflux. Then iron powder (0.5 g, 8.9 mmol) was added in one portion. The mixture was stirred at reflux for 2 hours. Once starting material was consumed, the resultant mixture was filtered when it was hot, and the filtrate was concentrated to give a residue. The residue was purified by column chromatography (silica gel, dichloromethane/methanol=10:1) to give ethyl 2,6-dimethyl-7-oxo-6,7-dihydro-1H-pyrrolo[2,3-c]pyridine-3-carboxylate (1.5 g, 75%) as a brown solid. LRMS (M+H+) m/z: calcd 234.1. found 234. 1H NMR (400 MHz, d6-DMSO): δ 12.54 (s, 1H), 7.30 (d, J=5.1 Hz, 1H), 6.78 (d, J=5.1 Hz, 1H), 4.24 (q, J=5.1 Hz, 2H), 3.51 (s, 3H), 2.56 (s, 3H), 1.32 (t, J=5.1 Hz, 3H).

1. temperatureheated to reflux
2. stirringThe mixture was stirred
3. temperatureat reflux for 2 hours
4. customOnce starting material was consumed
5. filtrationthe resultant mixture was filtered when it
6. concentrationthe filtrate was concentrated
7. customto give a residue
8. customThe residue was purified by column chromatography (silica gel, dichloromethane/methanol=10:1)