反应详情

Under nitrogen atmosphere, 2-methoxy-1-[2,4,6-trihydroxy-3,5-di(3-methyl-2-buten-1-yl)phenyl]ethanone (300 mg, 0.897 mmol), anhydrous potassium carbonate powder (744 mg, 5.38 mmol), TBAB (tetrabutyl ammonium bromide, 434 mg, 1.346 mmol), and 3-fluoro-4-methoxybenzoyl chloride (388 mg, 2.057 mmol) were dissolved in toluene (84 mL), and refluxed for 6 hours. After cooling, toluene was removed, and then water (20 mL) was added. The aqueous solution was extracted with ethyl acetate. The combined organic phase was washed with water and saturated brine, and dried over anhydrous sodium sulfate. A brown residue was obtained after removal of solvent. The residue was dissolved in a 20 mL methanol-H2O (4:1) mixture, to which was added potassium hydroxide (1 g). The mixture was heated to reflux for 2 hours, then cooled to ambient temperature, acidified to pH 4 with 1N HCl solution, and extracted with dichloromethane three times. The combined organic phase was dried over anhydrous sodium sulfate, with removal of solvent. The crude product was purified by silica gel column chromatography (eluent: ethyl acetate/petroleum ether, 1:50) to give the desired compound (137.8 mg, yield 32.6%). 1H NMR (400 MHz, CDCl3): δ=12.89 (s, 1H), 7.94 (dt, 1H, J1=8.8 Hz, J2=2.0 Hz), 7.90 (dd, 1H, J1=8.8 Hz, J2=2.0 Hz), 7.08 (t, 1H, J=8.8 Hz), 6.36 (s, 1H), 5.27-5.23 (m, 2H), 3.99 (s, 3H,), 3.88 (s, 3H), 3.54 (d, 2H, J=6.8 Hz), 3.47 (d, 2H, J=6.8 Hz), 1.85 (s, 3H), 1.84 (s, 3H), 1.77 (s, 3H), 1.75 (s, 3H); LC-MS (ESI) m/z 469.5 [M+14]+.

1. temperaturerefluxed for 6 hours
2. temperatureAfter cooling
3. customtoluene was removed
4. additionwater (20 mL) was added
5. extractionThe aqueous solution was extracted with ethyl acetate
6. washThe combined organic phase was washed with water and saturated brine
7. dry with materialdried over anhydrous sodium sulfate
8. customA brown residue was obtained
9. customafter removal of solvent
10. dissolutionThe residue was dissolved in a 20 mL methanol-H2O (4:1) mixture, to which
11. additionwas added potassium hydroxide (1 g)
12. temperatureThe mixture was heated
13. temperatureto reflux for 2 hours
14. extractionextracted with dichloromethane three times
15. dry with materialThe combined organic phase was dried over anhydrous sodium sulfate, with removal of solvent
16. customThe crude product was purified by silica gel column chromatography (eluent: ethyl acetate/petroleum ether, 1:50)