反应详情

5-Methyl-3'-deoxyuridine, from Step 1, was dissolved in 150 mL of dry pyridine and 3.6 g (24 mmol) of t-butyldimethylsilyl chloride was added in 4 portions at 4 times (t): t=0 h, t=2 h, t=3 h and at t=3.75 h. After 4.5 h, 8 mL of methanol was added to the reaction mixture and the reaction mixture was stirred for 0.5 h, then concentrated under reduced pressure to approximately 25% of volume. The concentrated reaction mixture was diluted with ethyl acetate, washed with dilute aqueous sodium bicarbonate solution and then concentrated under reduced pressure. The residue was purified by column chromatography on a 5 cm×37 cm silica gel column eluted with 90% ethyl acetate in hexane. The fractions containing the desired product were combined and concentrated in vacuo to give 7.27 g (84.4% yield based on 24.19 mmol of 2',5'-bis(O-(4"-chloro)benzoyl)-5-methyl-3'-deoxyuridine) of 5'-O-(t-butyldimethylsilyl)-5-methyl-3'-deoxyuridine, [α]D23 =-19.6° (c, 1.42, MeOH). Analysis calculated for C16H28N2O5Si: C, 53.98; H, 7.91; N, 7.87. Found: C, 54.01; H, 7.85; N, 7.79.

1. customt=0 h, t=2 h, t=3 h
2. customat t=3.75 h
3. concentrationconcentrated under reduced pressure to approximately 25% of volume
4. customThe concentrated reaction mixture
5. washwashed with dilute aqueous sodium bicarbonate solution
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified by column chromatography on a 5 cm×37 cm silica gel column
8. washeluted with 90% ethyl acetate in hexane
9. additionThe fractions containing the desired product
10. concentrationconcentrated in vacuo