A mixture of methyl 4-{[4-[(2,4-difluorobenzyl)oxy]-2-methyl-6-oxopyrimidin-1(6H)-yl]methyl}benzoate (0.20 g, 0.0005 mol, from step 3) and 2N NaOH (0.4 mL, 0.0008 mol) in dioxane (0.25 mL) is stirred at room temperature for 45 min. The resulting clear solution is diluted with water (5.0 mL), acidified with acetic acid and extracted with dichloromethane (2×10 mL). The combined organic extracts are washed with water (2×10 mL), dried (Na2SO4), filtered and concentrated to dryness to afford the title compound (0.15 g, 78%) as a white powder: 1H NMR (CD3OD/400 MHz) δ 7.99 (d, 2H, J=8.0 Hz), 7.54 (m, 1H,), 7.27 (d, 2H, J=8.0 Hz), 6.00 (m, 2H), 5.78 (s, 1H), 5.39 (s, 2H), 5.32 (s, 2H), 2.45 (s, 3H), and 2.13 (s, 3H); ES-HRMS m/z 387.1134 (M+H calcd for C20H17N2O4F2 requires 387.1151). 19F NMR (CD3OD/400 MHz) −111.79 (m) and −116.08 (m).
