3-benzyl-5-(3-fluoro-4-methoxyphenyl)-2-(methylthio)pyrimidin-4(3H)-one (697.4 mg, 1.957 mmol) was dissolved in 1,4-dioxane (10 ml) and 4-fluoroaniline (1.50 ml, 15.6 mmol) and concentrated hydrochloric acid (0.040 ml, 1.1 mmol) were added. The flask was fitted with a reflux condenser and placed in a preheated oil bath (125 C) and stirred under nitrogen. After stirring for 70 hours, the reaction was cooled to room temperature and concentrated. It was then treated with Et2O, and filtered, and the solid was washed with Et2O and dried in vacuo to afford the desired 3-benzyl-5-(3-fluoro-4-methoxyphenyl)-2-(4-fluorophenylamino)pyrimidin-4(3H)-one (582.7 mg, 1.39 mmol, 96% purity, 67% yield over two steps). MS (ESI pos. ion) m/z: 420 (MH+). Calc'd exact mass for C24H19F2N3O2: 419. 1HNMR (400 MHz, CDCl3): 7.89 (br s, 1H), 7.53-7.37 (m, 8H), 7.13 dd, J=9.2 Hz, 4.0 Hz, 2H), 7.01 (t, J=8.0 Hz, 3H), 5.47 (s, 2H), 3.93 (s, 3H).
