Reaction Steps
As described for the synthesis of 6-(morpholin-1-yl)-9-[2-deoxy-3,5-bis-O-(tert-butyldimethylsilyl)-β-D-erythro-pentofuranosyl]purine, this morpholino derivative was prepared by a reaction between O6-(benzotriazol-1-yl)-2′-deoxyinosine (28) (36.9 mg, 0.100 mmol), and morpholine (17.5 μL, 0.200 mmol) in the presence of Cs2CO3 (65.2 mg, 0.200 mmol) in dry DME (1.0 mL) at room temperature over 1 h. Chromatographic purification (SiO2, elution with 5% MeOH in CH2Cl2) afforded 16.6 mg (52% yield) of the title compound as a clear gum. Rf (10% MeOH in CH2Cl2)=0.34. 1H NMR (500 MHz, CDCl3): δ 8.26 (s, 1H, Ar—H), 7.77 (s, 1H, Ar—H), 6.88 (br, 1H, OH, CD3OD exchangeable), 6.30 (dd, 1H, H-1′, J=9.8, 5.4), 4.77 (d, 1H, H-3′, J=4.8), 4.30 (br, 4H, 2CH2), 4.21 (br s, 1H, H-4′), 3.96 (dd, 1H, H-5′, J=12.7, 1.2), 3.81 (t, 4H, 2CH2, J=4.9), 3.77 (br d, 1H, H-5′, J=13.2), 3.10 (ddd, 1H, H-2′, J=13.7, 9.3, 4.9), 2.65 (br, 1H, OH, CD3OD exchangeable), 2.26 (dd, 1H, H-2′, J=13.7, 5.6). 13C NMR (126 MHz, CDCl3): δ 154.1, 151.6, 149.4, 138.3, 121.7, 89.7, 87.8, 73.6, 67.0, 63.5, 45.6, 40.5.
