反应详情

A sample of the compound from Step 2b (330 mg) was stirred in a solution of water (0.5 mL) and acetic acid (0.25 mL) in acetonitrile (2 mL) for 2 hours. The mixture was diluted with ethyl acetate and washed with saturated aqueous sodium bicarbonate solution. The organic phase was washed with water and brine, dried over MgSO4, and concentrated in vacuo. The residue was re-treated with the same procedure (4 hours) to hydrolyse remaining protecting groups. The product was re-isolated as described, then purified by chromatography on silica gel, eluting with 1:98:1 methanol/dichlomethane/ammonium hydroxide to give the title compound (78 mg). 13C NMR (CDCl3) δ 82.6(C-9), 175.4(C-1), 153.4(carbonate carbonyl carbon), 102.9, 96.2, 88.6, 85.8, 84.0, 82.8, 80.3, 79.7, 77.9, 76.8, 72.6, 70.9, 68.9, 65.6, 65.4, 49.4, 44.9, 40.2, 39.6, 39.2, 34.9, 34.4, 28.6, 28.5, 21.8, 21.5,21.4, 19.8, 18.6, 17.8, 16.5, 15.9, 15.5, 9.9, 9.2. MS FAB High Resolution (M+H)+ : calcd: 787.4592; observed: 787.4606.

1. washwashed with saturated aqueous sodium bicarbonate solution
2. washThe organic phase was washed with water and brine
3. dry with materialdried over MgSO4
4. concentrationconcentrated in vacuo
5. additionThe residue was re-treated with the same procedure (4 hours) to hydrolyse
6. customThe product was re-isolated
7. custompurified by chromatography on silica gel
8. washeluting with 1:98:1 methanol/dichlomethane/ammonium hydroxide