反应详情

To a stirred solution of Intermediate 1G (2 g, 7.11 mmol) in anhydrous acetonitrile (30 mL) at room temperature, NBS (1.30 g, 7.11 mmol) was added in one portion. The resulting mixture was stirred at room temperature in the dark for 24 hours. The solvent was removed under reduced pressure and the residue was diluted with ethyl acetate. A saturated aqueous solution of sodium sulfite was added and the biphasic mixture was stirred vigorously at room temperature for 30 minutes. The aqueous phase was separated and the organic layer was washed twice with brine, dried over anhydrous MgSO4, filtered and evaporated under reduced pressure to give the crude product which was purified by column chromatography (silica), eluting with ethyl acetate/hexane mixtures to give Intermediate 1H as a white solid at 60% yield. 1H-NMR (400 MHz, CDCl3) δ: 1.52 (s, 9H), 3.85 (m, 2H), 3.89 (s, 3H), 3.93 (m, 2H), 4.89 (s, 2H). LCMS (+ESI) m/z 362.16 [M+H]+, 360.16 [M+H]+.

1. customThe solvent was removed under reduced pressure
2. additionthe residue was diluted with ethyl acetate
3. additionA saturated aqueous solution of sodium sulfite was added
4. stirringthe biphasic mixture was stirred vigorously at room temperature for 30 minutes
5. customThe aqueous phase was separated
6. washthe organic layer was washed twice with brine
7. dry with materialdried over anhydrous MgSO4
8. filtrationfiltered
9. customevaporated under reduced pressure
10. customto give the crude product which
11. customwas purified by column chromatography (silica)
12. washeluting with ethyl acetate/hexane