反应详情

n-Bromopentane (0.90 mL, 7.25 mmol, 1 eq) was added dropwise to a stirred solution of 3,4-dihydroxybenzaldehyde (1 g, 7.25 mmol, 1 eq) and cesium carbonate (7.07 g, 21.7 mmol, 3 eq) in N,N-dimethylformamide. The reaction mixture was stirred overnight and concentrated in vacuo. The residue was dissolved in ethyl acetate (50 mL), and the organic solution washed with water (2×50 mL), and brine (50 mL), then dried over magnesium sulfate and evaporated. Chromatography on silica with dichloromethane:petroleum ether (4:1) as eluent gave the product as a brown oil (367 mg, 24%). 1H NMR (CDCl3) δ 9.79 (s, 1H, O═C—H), 6.21 (s, 1H, OH), 4.08 (t, 2H, OCH2), 1.81 (m, 2H, OCH2CH2), 1.40 (m, 4H, CH2CH2CH3), 0.89 (t, 3H, CH3).

1. concentrationconcentrated in vacuo
2. dissolutionThe residue was dissolved in ethyl acetate (50 mL)
3. washthe organic solution washed with water (2×50 mL), and brine (50 mL)
4. dry with materialdried over magnesium sulfate
5. customevaporated