A mixture of 7-(1-aminoethyl)-6-(3,5-difluorophenyl)-5H-[1,3]thiazolo[3,2-a]pyrimidin-5-one (0.037 g, 0.12 mmol), 6-bromo-9H-purine (0.048 g, 0.24 mmol), and N,N-diisopropylethylamine (0.042 mL, 0.24 mmol) in ethanol (0.5 mL) was heated at 110° C. overnight. The mixture was filtered, and the filtrate was purified on preparative-LCMS (XBridge C18 Column, eluting with a gradient of acetonitrile/water containing 0.15% NH4OH) to give the desired product. LCMS calculated for C19H14F2N7OS (M+H)+: m/z=426.1. Found: 426.0. 1H NMR (DMSO-d6, 400 MHz) δ 7.99 (1H, d, J=4.8 Hz), 7.63 (1H, s), 7.53 (1H, d, J=4.8 Hz), 7.24 (1H, m), 7.16 (2H, m), 6.88 (1H, br s), 5.41 (2H, br s), 5.05 (1H, m), 1.27 (3H, d, J=6.8 Hz) ppm. 19F NMR (DMSO-d6, 376.3 MHz) δ −111 ppm.
