反应详情

Compound 4 (10 g, 34 mmol) was dissolved in THF (100 mL), then acetic acid (4.0 mL, 70 mmol) and tributylammoniumfloride (1.0 M in THF) (51 mL, 51 mmol) were added at room temperature. After stirring for 40 min at the same temperature, a saturated aqueous solution of NH4Cl (50 mL) was added, followed by extraction with ethyl acetate (3×60 mL), and the combined extracts was dried (Na2SO4). The solvent was removed under a vacuum, and the residue was purified by flash chromatography (dichloromethane) to give 5 (Rf=0.5, ethyl acetate/hexane 1:1) as a yellowish liquid (6.8 g, 90%). 1H NMR (500 MHz, CDCl3): δ 7.11 (s, 1H), 7.05 (s, 1H), 4.68 (s, 2H), 3.87 (s, 3H), 3.23 (s, 1 H), 2.38(s, 3H). 13C NMR (500 MHz, CDCl3): δ 168.85, 151.75, 140.85, 139.92, 122.99, 117.37, 111.86, 82.08, 78.54, 64.66, 56.31, 20.75.

1. extractionfollowed by extraction with ethyl acetate (3×60 mL)
2. dry with materialthe combined extracts was dried (Na2SO4)
3. customThe solvent was removed under a vacuum
4. customthe residue was purified by flash chromatography (dichloromethane)