Reaction Steps
To a stirred solution of nucleoside 34 (553 mg, 1.05 mmol) in methanol (5.5 cm3) was added sodium methoxide (287 mg, 5.25 mmol). The reaction mixture was stirred at room temperature for 10 min, then neutralised with dilute hydrochloric acid. The solvent was partly evaporated and extraction was performed with dichloromethane (2×20 cm3). The combined organic phase was washed with saturated aqueous sodium hydrogencarbonate (3×20 cm3) and was dried (Na2SO4). The solvent was removed under reduced pressure to give 35 as a white solid material (476 mg, 97%). δH (CDCl3) 7.47 (1H, d, J 1.0 6-H), 7.36-7.22 (10H, m, Bn), 6.07 (1H, d, J 3.8, 1′-H), 4.87 (1H, d, J 11.7, Bn), 4.55 (1H, d, J 11.7, Bn), 4.50-4.32 (4H, m, Bn, 2′-H, 3′-H), 3.84-3.53 (4H, m, 5′-Ha, 5′-Hb, 1″-Ha, 1″-Hb), 1.50 (3H, d, J 1.1, CH3). δC (CDCl3) 164.3 (C-4), 151.3 (C-2), 137.6 (C-6) 136.4, 136.3, 128.8, 128.6, 128.4, 128.3, 127,9 (Bn), 111.1 (C-5), 91.1, 91.0, 88.1 (C-1′, C-3′, C-4′), 77.4 (C-2′), 74.8, 73.8, 71.4, 63,2 (Bn, C-5′, C-1″), 12.0 (CH3). FAB-MS m/z 491 [M+Na]+. Found: C, 63.4; H, 6.0; N, 5.5: C25H28N2O7, 1/4H2O requires C, 63.5; H, 6.1; N, 5.9%.
