Following method A with 5′-amino-2′,3′-isopropylidene adenosine (2.21 g, 7.22 mmol, 1.00 eq) and 4-nitrobenzenesufonyl chloride, 18 (2.64 g, 74%) was obtained as a beige solid. Rf 0.50 (8:92 MeOH/DCM). 1H NMR (600 MHz, DMSO‑d 6) δ 8.55 (t, J = 5.8 Hz, 1H), 8.33–8.27 (m, 2H), 8.26 (s, 1H), 8.13 (s, 1H), 7.96–7.88 (m, 2H), 7.37 (br. s, 2H), 6.09 (d, J = 2.8 Hz, 1H), 5.32 (dd, J = 6.3 Hz, 2.9 Hz, 1H), 4.89 (dd, J = 6.3 Hz, 3.0 Hz, 1H), 4.16 (td, J = 5.9 Hz, 3.0 Hz, 1H), 3.24–3.10 (m, 2H), 1.50 (s, 3H), 1.27 (s, 3H). 13C NMR (600 MHz, DMSO‑d 6) δ 156.3, 152.7, 149.5, 148.4, 146.0, 140.2, 128.0, 124.5, 119.3, 113.6, 89.4, 84.4, 83.0, 81.6, 44.6, 27.0, 25.2. HRMS (ESI+): m/z calcd for C19H22N7O7S [M+H]+: 492.1301, Found 492.1311.