Reaction Steps
To a stirred solution of nucleoside 1 (11.6 g, 22.3 mmol) in methanol (110 cm3) was added sodium methoxide (3.03 g, 55.5 mmol). The reaction mixture was stirred at room temperature for 16 h and neutralised with dilute hydrochloric acid. The solvent was partly evaporated and the residue was dissolved in dichloromethane (2×400 cm3). The organic phase was washed with a saturated aqueous solution of sodium hydrogencarbonate (3×250 cm3) and dried (Na2SO4). The solvent was removed under reduced pressure to give 2 as a white solid material (10.1 g, 95%). δH (CDCl3) 8.77 (1 H, br s, NH), 7.58 (1 H, d, J 1.2, 6-H), 7.41-7.25 (10 H, m, Bn), 6.14 (1H, m, 2″-H), 6.12 (1 H, d, J 7.8, 1′-H), 5.23 (1 H, m, 3″-Ha), 5.17 (1 H, br s, 3″-Hb), 4.68 (1 H, d, J 10.8, Bn), 4.59 (2 H, s, Bn), 4.55 (1 H, d, J 10.9, Bn), 4.39 (1 H, br s, 4′-H), 4.26 (1 H, dd J 7.8, 10.7, 2′-H), 3.84 (1 H, dd, J 3.1, 11.0, 5′-Ha), 3.58 (1 H, dd, J 1.4, 11.0, 5′-Hb), 3.04 (1 H, d, J 10.8, 2′-OH), 2.82-2.78 (2 H, m, 1″-Ha, 1″-Hb), 1.51 (3 H, d, J 1.0, CH3). δC (CDCl3) 163.5 (C-4), 151.1 (C-2), 137.3, 136.7 (Bn), 136.0 (C-6), 132.1 (C-2″), 128.8, 128.5, 128.3, 127.9, 127.6 (Bn), 118.4 (C-3″), 111.1 (C-5), 87.4, 82.6, 81.1, 79.3 (C-1′, C-2′, C-3′, C-4′), 73.7, 69.8 (Bn), 64.7 (C-5′), 35.1 (C-1″), 11.9 (CH3). (Found: C, 67.8; H, 6.1; N, 5.5. C27H30N2O6 requires C, 67.8; H, 6.3; N, 5.9%).
