4.1.14  9-[(2R,5R)-3-[2-({[(4R,6R)-6-(6-amino-9H-purin-9-yl)-2,2-dimethyl-tetrahydro-2H-furo[3,4-d] [1,3]dioxol-4-yl]methyl}(butyl)amino)ethoxy]-4-[(tert-butyldimethylsilyl)oxy]-5-{[(tert-butyldimethylsilyl)oxy]methyl}oxolan-2-yl]-9H-purin-6-amine (23)
Following method D with 20 (80 mg, 97 μmol, 1.00 eq) and 1-bromobutane, 23 (40 mg, 47%) was obtained as a white solid. Rf 0.48 (MeOH/DCM 5:95). 1H NMR (600 MHz, CDCl3) δ 8.33 (s, 2H), 8.16 (s, 1H), 7.92 (s, 1H), 6.11 (d, J = 3.8 Hz, 1H), 6.03 (d, J = 2.3 Hz, 1H), 5.77 (br. s, 4H), 5.47 (dd, J = 6.4 Hz, J = 2.2 Hz, 1H), 4.91 (dd, J = 6.4 Hz, J = 3.2 Hz, 1H), 4.51 (t, J = 5.1 Hz, 1H), 4.37–4.24 (m, 2H), 4.09 (dt, J = 5.9 Hz, J = 3.0 Hz, 1H), 3.99 (dd, J = 11.5 Hz, J = 3.7 Hz, 1H), 3.76 (dd, J = 11.5 Hz, J = 2.8 Hz, 1H), 3.70–3.61 (m, 2H), 2.77–2.68 (m, 3H), 2.63 (dd, J = 13.5 Hz, J = 7.0 Hz, 1H), 2.46–2.37 (m, 2H), 1.59 (s, 3H), 1.38 (s, 3H), 1.31–1.22 (m, 2H), 1.22–1.12 (m, 2H), 0.92 (s, 9H), 0.91 (s, 9H), 0.82 (t, J = 7.3 Hz, 3H), 0.10–0.08 (m, 12H). 13C NMR (150 MHz, CDCl3) δ 155.6, 155.5, 153.2, 153.1, 149.8, 149.4, 140.2, 139.7, 120.5, 120.3, 114.4, 91.2, 87.2, 85.8, 84.9, 84.0, 83.4, 82.4, 69.9, 69.3, 62.0, 56.7, 55.1, 53.9, 29.2, 27.2, 26.1, 25.9, 25.5, 20.5, 18.6, 18.2, 14.1, −4.4, −4.6, −5.2, −5.2. HRMS (ESI+): m/z calcd for C46H72N11O7Si2 [M+H]+: 884.4998, found: 884.5002.