反应详情

温度

40 °C

To a solution of (1S,2S,3S,4R,5S)-2,3,4-tribenzyloxy-5-[4-chloro-3[(4-ethoxyphenyl)methyl]phenyl]-6,8-dioxabicyclo[3.2.1]octane-1-carboxylic acid 2a (0.38 g, 0.53 mmol) in methanol (8 mL) was added concentrated sulphuric acid (56.9 mg, 0.58 mmol) at room temperature. The mixture was stirred at 40° C. for 12 hours and quenched with 0.5 mL of saturated aqueous sodium hydrogen carbonate. Most of the solvent of the mixture was removed in vacuo. To the residue was added water (10 mL). The resulting mixture was extracted with ethyl acetate (10 mL×2). The combined organic layers were washed with saturated aqueous sodium chloride (10 mL×2), dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was purified by silica gel chromatography eluted with PE/EtOAc(v/v)=10/1 to give the title compound 2b as colorless oil (155 mg, 41.4%). The compound was characterized by the following spectroscopic data: 1H NMR (400 MHz, CDCl3) δ(ppm): 7.48 (m, 1H), 7.39 (m, 2H), 7.38-7.29 (m, 7H), 7.28-7.23 (m, 3H), 7.19 (m, 3H), 7.08 (m, 2H), 6.91-6.86 (m, 2H), 6.80-6.73 (m, 2H), 4.82 (m, 3H), 4.63 (d, 1H), 4.53 (d, 1H), 4.26 (d, 1H), 4.24-4.16 (m, 2H), 4.09 (d, 1H), 4.05-3.94 (m, 4H), 3.87 (d, 1H), 3.75 (d, 1H), 3.71 (s, 3H), 1.41 (t, 3H).

1. customquenched with 0.5 mL of saturated aqueous sodium hydrogen carbonate
2. customMost of the solvent of the mixture was removed in vacuo
3. additionTo the residue was added water (10 mL)
4. extractionThe resulting mixture was extracted with ethyl acetate (10 mL×2)
5. washThe combined organic layers were washed with saturated aqueous sodium chloride (10 mL×2)
6. dry with materialdried over anhydrous sodium sulfate
7. concentrationconcentrated in vacuo
8. customThe residue was purified by silica gel chromatography
9. washeluted with PE/EtOAc(v/v)=10/1