反应详情

Chromium trioxide (7.63 g, 76.3 mmol) was added to 150 mL of dry methylene chloride containing 12.059 g (152.6 mmol) of pyridine. The mixture was stirred for 15 minutes. In a separate flask, 793 mg (19.08 mmol) of 5'-O-(t-butyldimethylsilyl)-5-methyl-3'-deoxyuridine from Step 2 was dissolved in approximately 100 mL of methylene chloride. The chromium trioxide-pyridine solution was added to the solution of 5'-(t-butyldimethylsilyl)-5-methyl-3'-deoxy-uridine and 1.946 g (19.08 mmol) of acetic anhydride was added immediately. After stirring at ambient temperature for 0.5 h, the reaction mixture was diluted with approximately 250 mL of ethyl acetate then filtered through Celite filter aid and through florisil eluted with ethyl acetate. The solvent was evaporated and the residue purified on silica gel eluted with 90% ethyl acetate in hexanes. The title compound was obtained in 59.6% yield (4.08 g), [α]D23 =+38.0° (c, 1.31, MeOH). Analysis calculated for C16H26N2O5Si: C, 54.24; H, 7.34; N, 7.91. Found: C, 54.25; H, 7.36; N, 7.88

1. additionwas added immediately
2. stirringAfter stirring at ambient temperature for 0.5 h
3. filtrationthen filtered through Celite
4. filtrationfilter aid
5. washthrough florisil eluted with ethyl acetate
6. customThe solvent was evaporated
7. customthe residue purified on silica gel
8. washeluted with 90% ethyl acetate in hexanes