反应详情

To a solution of 5-hydroxy-2,2-dimethyl-6-propionyl-10-propyl-2H-pyrano[2,3-f]chromen-8-one (30) (3.40 g, 10 mmol, 1.0 eq) in DMF (60 mL) was added potassium carbonate (13.8 g 100 mmol, 10.0 eq) followed by 2-bromoethyl acetate (5 g, 30 mmol, 3.0 eq). The reaction mixture was stirred for 2 days at ambient temperature, which was partitioned between water (600 mL) and ethyl acetate (300 ml). The organic layer was washed with an additional portion of water (600 mL), dried and concentrated. The solid residue was re-dissolved in methanol (200 mL) followed by addition of 2 N aqueous sodium hydroxide (20 mL). The mixture was stirred for 2 h at room temperature, pH adjusted to 6.0 with concentrated hydrochloric acid and concentrated under vacuum. The residue was partitioned between water (200 mL) and ethyl acetate (200 mL). The organic layer was separated, washed successively with water (100 mL) and brine (100 mL), dried over anhydrous sodium sulfate and concentrated under vacuum. The solid residue was crystallized from cyclohexane/ethanol 80/20 and re-crystallized from methanol/water 95/5, affording 1.23 g of 31e (32% yield). 1H NMR (CDCl3): 1.05 (t, J=7.5 Hz, 3H), 1.21 (t, J=7.5 Hz, 3H), 1.52 (s, 6H), 1.67 (m, 2H), 2.92 (m, 4H), 3.29 (t, J=6.5 Hz, 1H), 3.81 (m, 2H), 4.13 (m, 2H), 5.66 (d, J=10.0 Hz, 1H), 6.03 (s, 1H), 6.54 (J=10.0 Hz, 1H); 13C NMR (CDCl3): 7.99, 13.89, 23.04, 27.60, 38.50, 38.54, 62.01, 78.08, 78.41, 106.17, 110.77, 112.63, 116.92, 117.04, 128.47, 152.27, 153.12, 154.78, 157.39, 159.38, 203.60; IR: 1708 cm−1; MS (ACPI+): 387 (M+1); Anal. Calcd. for C22H26O6: C 68.38, H 6.78; Found: C 68.21, H 6.90.

1. customwhich was partitioned between water (600 mL) and ethyl acetate (300 ml)
2. washThe organic layer was washed with an additional portion of water (600 mL)
3. customdried
4. concentrationconcentrated
5. dissolutionThe solid residue was re-dissolved in methanol (200 mL)
6. additionfollowed by addition of 2 N aqueous sodium hydroxide (20 mL)
7. stirringThe mixture was stirred for 2 h at room temperature
8. concentrationconcentrated under vacuum
9. customThe residue was partitioned between water (200 mL) and ethyl acetate (200 mL)
10. customThe organic layer was separated
11. washwashed successively with water (100 mL) and brine (100 mL)
12. dry with materialdried over anhydrous sodium sulfate
13. concentrationconcentrated under vacuum
14. customThe solid residue was crystallized from cyclohexane/ethanol 80/20
15. customre-crystallized from methanol/water 95/5