Potassium Carbonate → HCID 5270961, compound

Participants

Reaction Steps

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.

Provenance & Evidence