4.1.31 N-{[(2R,5R)-5-(6-amino-9H-purin-9-yl)-3,4-dihydroxyoxolan-2-yl]methyl}-N-(2-{[(2R,5R)-2-(6-amino-9H-purin-9-yl)-4-hydroxy-5-(hydroxymethyl)oxolan-3-yl]oxy}ethyl)-2-methoxy-4-nitrobenzene-1-sulfonamide (11) Using method C with 31 (160 mg, 0.15 mmol, 1.00 eq) and a 0–40% linear gradient of acetonitrile in TEAAc buffer 50 mM, pH 7 for purification, 11 (15 mg, 13%) was obtained as a white powder with 98% purity determined by HPLC analysis at 260 nm. 1H NMR (500 MHz, DMSO‑d 6) δ 8.32 (s, 1H), 8.28 (s, 1H), 8.13 (s, 2H), 7.77 (d, J = 9.0 Hz, 1H), 7.44 (dd, J = 8.5 Hz, J = 2.6 Hz, 1H), 7.34 (br. s, 2H), 7.29 (br. s, 2H), 6.99 (dd, J = 9.0 Hz, J = 2.6 Hz, 1H), 5.95 (d, J = 5.2 Hz, 1H), 5.83 (d, J = 5.5 Hz, 1H), 5.65 (br. s, 1H), 5.49 (br. s, 1H), 5.38 (t, J = 5.7 Hz, 1H), 5.27 (br. s, 1H), 4.66 (t, J = 5.2 Hz, 1H), 4.37 (t, J = 5.1 Hz, 1H), 4.33–4.27 (m, 1H), 4.17–4.08 (m, 2H), 3.93 (q, J = 3.6 Hz, 1H), 3.84 (s, 3H), 3.80–3.62 (m, 3H), 3.60–3.37 (m, 5H). 13C NMR (125 MHz, DMSO‑d 6) δ 156.9, 156.1, 155.9, 152.5, 152.4, 150.6, 149.0, 148.8, 134.0, 139.5, 133.7, 131.0, 119.2, 119.2, 114.4, 107.4, 87.8, 86.2, 85.9, 81.5, 81.4, 72.5, 71.3, 68.9, 66.7, 61.1, 56.8, 50.2, 47.1. HRMS (ESI+): m/z calcd for C29H35N12O12S [M+H]+: 775.2218, Found 775.2220.