反应详情

3-(1,1-Dimethylheptyl)-1-hydroxy-9-methoxy-6H-dibenzo[b,d]pyran-6-one (4b) (200 mg, 0.54 mmol) was dissolved in 12 mL of dry dichloromethane, 2 mL of a 1M solution of boron tribromide in dichloromethane (2 mmol) was added and the resulting mixture was stirred at room temperature for 3 days. Water was added and the mixture was extracted with diethyl ether. The organic extract was dried and rotary evaporated. The residue was chromatographed on silica gel (50% ethyl ether-petroleum ether) to afford 150 mg of a flaky off-white foam: m.p. 103-108° C.; Rf; 0.28 (50% diethyl ether-petroleum ether); 1H NMR δ 8.60 (m, 1H), 8.35 (d, 1H), 7.05 (d, 1H), 6.90 (s, 1H), 6.73 (s, 1H), 6.10 (br s, 2H), 1.70-0.98 (series of m, 10H), 1.27 (s, 6H), 0.82 (t, J=6.6 Hz, 3H); Anal. calcd. for C23H28O4 74.55% C, 7.39% H. Found 72.70% C, 7.25% H.

1. extractionthe mixture was extracted with diethyl ether
2. extractionThe organic extract
3. customwas dried
4. customThe residue was chromatographed on silica gel (50% ethyl ether-petroleum ether)