反应详情

A mixture of ethyl 2-cyano-5-(dimethylamino)-3-ethoxypenta-2,4-dienoate (150 g, 0.63 mol) and HOAc (600 mL) was refluxed overnight. The mixture was concentrated to dryness under high vacuum and the residue treated with water (300 mL). The mixture was extracted with EtOAc (2×250 mL) to remove the impurities. The pH of the aqueous was adjusted with NaHCO3 to pH ˜9-10. The mixture was extracted with CH2Cl2 (3×300 mL). The combined organics were washed with brine, dried over Na2SO4 and concentrated. The residue was purified by silica gel chromatography to afford ethyl 4-ethoxy-2-oxo-1,2-dihydropyridine-3-carboxylate (90 g, 66.6% yield).

1. temperaturewas refluxed overnight
2. concentrationThe mixture was concentrated to dryness under high vacuum
3. additionthe residue treated with water (300 mL)
4. extractionThe mixture was extracted with EtOAc (2×250 mL)
5. customto remove the impurities
6. extractionThe mixture was extracted with CH2Cl2 (3×300 mL)
7. washThe combined organics were washed with brine
8. dry with materialdried over Na2SO4
9. concentrationconcentrated
10. customThe residue was purified by silica gel chromatography