反应详情

A suspension of 102.0 g (0.361 mol) of 2-(5-nitro-2-pyridyl)-1,3-propanedicarboxylate, from Step 1, in 600 mL of 20% aqueous sulfuric acid solution was heated at 95° C. for 24 hours. The resultant solution was poured onto 1 kg of ice and the aqueous mixture was adjusted to a pH within the range pH 10-12 with 50% aqueous sodium hydroxide solution. The precipitate was filtered and dissolved in ethyl acetate. The ethyl acetate solution was dried over anhydrous sodium sulfate, filtered and concentrated to a solid residue. The residue was washed with hexane. The hexane was removed by filtration and the solid was dried to afford 45.86 g (92% yield) of the title compound; 1H NMR (CDCl3) d 2.71 (s, 3H), 7.36 (d, 1H, J=9.0 Hz), 8.37 (dd, 1H, J=3.0 Hz, 9.0 Hz), 9.33 (d, 1H, J=3.0 Hz).

1. filtrationThe precipitate was filtered
2. dissolutiondissolved in ethyl acetate
3. dry with materialThe ethyl acetate solution was dried over anhydrous sodium sulfate
4. filtrationfiltered
5. concentrationconcentrated to a solid residue
6. washThe residue was washed with hexane
7. customThe hexane was removed by filtration
8. customthe solid was dried