反应详情

A solution of 25.0 g (93.6 mmol) of 5'-azido-5'-deoxythymidine (which can be prepared as in reference 36), 21.1 g (140 mmol) of t-butyldimethylsilyl chloride, and 12.7 g (187 mmol) imidazole in 190 ml of anhydrous DMF was stirred at RT under nitrogen for 18 hr. The DMF was removed under vacuum. The oil was partitioned between ether (500 ml) and 1N NaOH (2×300 ml). The aqueous layers were cooled with ice, and 650 ml of 1N HCl were added. The product was extracted with EtOAc (2×750 ml), and the organic layer was washed with brine, dried, and evap. After remaining under high vacuum for 24 hr, the oil crystallized to give 27.9 g of 5'-azido-3'-O-t-butyldimethylsilyl-5'-deoxythymidine as a white solid: NMR (300 MHz,d6-DMSO) δ11.34 (br,1H), 7.50 (s,1H), 6.16 (t,1H,J=7 Hz), 4.36 (m,1H), 3.84 (m,1H), 3.55 (m,2H), 2.34 (m,1H), 2.05 (m,1H), 1.79 (s,3H), 0.86 (s,9H), 0.08 (s,6H).

1. customThe DMF was removed under vacuum
2. customThe oil was partitioned between ether (500 ml) and 1N NaOH (2×300 ml)
3. temperatureThe aqueous layers were cooled with ice, and 650 ml of 1N HCl
4. additionwere added
5. extractionThe product was extracted with EtOAc (2×750 ml)
6. washthe organic layer was washed with brine
7. customdried
8. customthe oil crystallized