4.1.25  N-{[(4R,6R)-6-(6-amino-9H-purin-9-yl)-2,2-dimethyl-tetrahydro-2H-furo[3,4-d] [1,3]dioxol-4-yl]methyl}-4-chloro-3-nitrobenzene-1-sulfonamide (29)
Following method A with 5′-amino-2′,3′-isopropylidene adenosine (280 mg, 0.92 mmol, 1.00 eq) and 4-chloro-3-nitrobenzenesufonyl chloride, 29 (346 mg, 72%) was obtained as a brown solid. Rf 0.42 (8:92 MeOH/CH2Cl2). 1H NMR (400 MHz, DMSO‑d 6) δ 8.56 (s, 1H), 8.39 (d, J = 2.1 Hz, 1H), 8.27 (s, 1H), 8.14 (s, 1H), 7.96 (dd, J = 8.5 Hz, J = 2.1 Hz, 1H), 7.90 (d, J = 8.5 Hz, 1H), 7.37 (br. s, 2H), 6.12 (d, J = 2.8 Hz, 1H), 5.34 (dd, J = 6.3 Hz, J = 2.9 Hz, 1H), 4.89 (dd, J = 6.3 Hz, J = 3.1 Hz, 1H) 4.17 (td, J = 5.9 Hz, J = 3.0 Hz, 1H), 3.33–3.18 (m, 2H), 1.51 (s, 3H), 1.29 (s, 3H). 13C NMR (100 MHz, DMSO‑d 6) δ 156.7, 153.0, 148.9, 147.8, 141.1, 140.6, 133.4, 131.6, 129.8, 124.4, 119.7, 114.0, 107.7, 89.8, 84.7, 83.4, 82.0, 44.9, 27.4, 25.6. HRMS (ESI+): m/z calcd for C19H21N7O7SCl [M+H]+: 526.0912, Found 526.0914.