To a suspension of Example 3B (100 mg) and diisopropylamine (0.25 mL) in degassed DMF (1 mL) was added sequentially 6-iodopurine (89 mg), copper iodide (3.5 mg) and tetrakis(triphenylphosphine)palladium (21 mg). The mixture was heated to 60° C. for 4 hours. Next, the reaction mixture was cooled to room temperature and concentrated. The resultant material was dissolved in dichloromethane (4 mL), then filtered. The precipitate was washed with water (10 mL), then cold acetone (3 mL) to provide the desired solid. MS (ESI(+)) m/e 395 (M+H)+; 1H NMR (300 MHz, DMSO) δ 8.91 (s, 1H), 8.69 (s, 1H), 8.25 (t, J=5.7 Hz, 1H), 7.89 (m, 1H), 7.82 (t, J=9 Hz, 1H), 7.7 (dd, J=2.1, 12.3 Hz, 1H), 7.5 (dd, J=2.1, 9 Hz, 1H), 4.78 (m, 1H), 4.19 (t, J=9 Hz, 1H), 3.8 (dd, J=6.3, 9.6 Hz, 1H), 3.44 (t, J=5.7 Hz, 2H), 1.84 (s, 3H).
