2,2,2-Trifluoro-N-(4-hydroxymethyl-benzyl)-acetamide (138 mg, 0.59 mmol) is dissolved in 3 mL dry dimethylacetamide under argon atmosphere, and (31 mg, 1.31 mmol) NaH is added. N9-(3-Azidopropyl)-2-amino-6-chloropurine (22, 100 mg, 0.39 mmol) is added and the solution heated to 90° C. for 16 h. After cooling to room temperature, the mixture is poured into 80 mL of water and the pH is adjusted to 6 with trifluoroacetic acid. The aqueous phase is extracted with CH2Cl2 and ethyl acetate. The organic phases are washed with water and brine, dried over MgSO4 and the solvent is evaporated. The crude product is dissolved in methanol, adsorbed on SiO2 (150 mg) and purified by flash column chromatography with dichloromethane:methanol (95:5). Yield: 151 mg (0.0336 mmol, 85%). 1H-NMR (400 MHz, DMSO-d6): δ=10.00 (t, J=5.8, 1H, CF3CONH), 7.90 (s, 1H, H-8), 7.49, (d, J=8.1, 2H, ArH), 7.28 (d, J=8.1, 2H, ArH), 6.47 (s br, 2H, NH2), 5.46 (s, 2H, OCH2), 4.38 (d, J=5.8, 2H, CH2NH), 4.06 (t, J=6.5, 2H, CH2), 3.36 (t, J=6.5, 2H, CH2), 2.00 (m, 2H, CH2) ppm. MS (ESI) m/z 450.0 [M+H]+.
