Reaction Steps
As described for the synthesis of 3′,5′-bis-O-(tert-butyldimethylsilyl)-O6-(4-nitrophenyl)-2′-deoxyinosine, this quinolinyl derivative was prepared by a reaction between O6-(benzotriazol-1-yl)-2′,3′,5′-tris-O-(tert-butyldimethylsilyl)inosine (27) (71.8 mg, 0.099 mmol), Cs2CO3 (65.2 mg, 0.200 mmol) and 8-hydroxyquinoline (16.0 mg, 0.110 mmol) in dry DME (1.0 mL) at 85° C. for 1 h. Chromatographic purification (SiO2, elution with 50% EtOAc in hexanes) afforded 52.9 mg (72% yield) of the title compound as a white foam. Rf (50% EtOAc in hexanes)=0.58. 1H NMR (500 MHz, CDCl3): δ 8.74 (m, 1H, Ar—H), 8.48 (s, 1H, Ar—H), 8.33 (s, 1H, Ar—H), 8.20 (m, 1H, Ar—H), 7.79 (d, 1H, Ar—H, J=8.3), 7.67-7.60 (m, 2H, Ar—H), 7.39 (dd, 1H, Ar—H, J=8.5, 4.2), 6.13 (d, 1H, H-1′, J=4.4), 4.63 (t, 1H, H-2′, J=4.4), 4.37 (t, 1H, H-3′, J=4.1), 4.17 (m, 1H, H-4′), 4.07 (dd, 1H, H-5′, J=11.2, 3.4), 3.83 (dd, 1H, H-5′, J=11.2, 2.4), 0.97, 0.94, 0.84 (3S, 27H, tert-Bu), 0.17, 0.15, 0.12, 0.11, 0.0, −0.11 (6 s, 18H, SiCH3). 13C NMR (126 MHz, CDCl3): δ 161.0, 152.9, 151.9, 150.2, 149.1, 141.9, 141.5, 135.9, 129.7, 126.4, 125.9, 122.0, 121.6, 121.5, 88.7, 85.1, 76.2, 71.5, 62.3, 26.1, 25.8, 25.7, 18.6, 18.1, 17.9, −4.3, −4.7, −4.73, −4.9, −5.3, −5.4. FAB HRMS calcd for C37H60N5O5Si3 (M++H) 738.3902. found 738.3885.
