Reaction Steps
A stirring solution of thymidine (50.0 g, 207 mmol) and DMAP (10 mg, 8.2×10−2 mmol) in 400 mL of pyridine was treated with TBDPSCl (43.4 g, 248 mmol) at 25° C. for 16 h. The solvent was removed under reduced pressure and the residue was diluted with 1 L of AcOEt. The mixture was washed with 5% aqueous HCl (2×100 mL) and H2O (100 mL). The organic layer was dried (MgSO4) and concentrated under reduced pressure. The product was purified by silica gel chromatography (CH2Cl2/MeOH 20:1) to give 87.3 g (88%) of 2 as a white solid. An analytical sample was crystallized from diethylether. mp 164-166° C. (170-171° C. per Matulic-Adamic, J. Chem. Soc., Chem. Comm. 1985, 21, 1535) Rf(CH2Cl2/MeOH 10:1) 0.31. 1H-NMR (CDCl3): 1.08 (s, 9H, C-Me3), 1.61 (s, 3H, 5-Me), 2.18 (ddd, 1H, J=13.8, 8.5, 6.0 Hz, 2Hβ), 2.19 (br s, 1H, D2O exchangeable, 3′-OH), 2.44 (ddd, 1H, J=13.8, 5.6, 2.1 Hz, 2′-Hα), 3.25 (br s, 1H, 5′-OH, D2O exchangeable), 3.85 (dd, 1H, J=11.5, 2.5 Hz, 5′-CHH), 3.98 (dd, 1H J=11.5, 2.3 Hz, 5′-CHH), 4.06 (dd, 1H, J=2.5, 2.3 Hz, 4′H), 4.55 (dd, 1H J=6.0, 5.6 Hz, 3′-H), 6.43 (dd, 1H, J=8.5, 5.6 Hz, 1′-H), 7.26-7.51 (m, 6H, aromatic-H), 7.64-7.68 (m, 5H, 6-H and aromatic-H), 9.57 (s, 1H, NH, D2O exchangeable).
