反应详情

A solution of 399 mg (1.70 mmol) of 4-(4-nitro-phenyl)-dihydro-pyran-2,6-dione (as prepared in Example 2, step (b)) in THF (8 mL) was treated with 1.10 mL (2.21 mmol) of 2.0 M methylamine in THF. The mixture was stirred at RT for 45 min, concentrated in vacuo, taken up in 1 N aqueous HCl (10 mL), and extracted with EtOAc (2×20 mL). The combined organic layers were dried (MgSO4) and concentrated in vacuo. The residue was taken up in acetic anhydride (7 mL), treated with triethylamine (1 mL) and heated to 80° C. for 1 h. The solvents were removed in vacuo. The residue was taken up in EtOAc (20 mL) and washed successively with 1 N aqueous HCl, saturated aqueous NaHCO3, and water (1×10 mL each). The organic layer was dried (MgSO4) and concentrated in vacuo. Silica gel chromatography of the residue with 25-50% EtOAc-hexane afforded 348 mg (83%) of the title compound as an off-white solid: 1H-NMR (CDCl3; 400 MHz): δ 8.25 (d, 2H, J=8.8 Hz), 7.40 (d, 2H, J=8.8 Hz), 3.56-3.45 (m, 1H), 3.21 (s, 3H), 3.10-3.01 (m, 2H), 2.88-2.77 (m, 2H).

1. concentrationconcentrated in vacuo
2. extractionextracted with EtOAc (2×20 mL)
3. dry with materialThe combined organic layers were dried (MgSO4)
4. concentrationconcentrated in vacuo
5. additiontreated with triethylamine (1 mL)
6. temperatureheated to 80° C. for 1 h
7. customThe solvents were removed in vacuo
8. washwashed successively with 1 N aqueous HCl, saturated aqueous NaHCO3, and water (1×10 mL each)
9. dry with materialThe organic layer was dried (MgSO4)
10. concentrationconcentrated in vacuo