To a cooled (0° C.) solution of methyl 3-[4-{[2-(aminomethyl)-4-fluorobenzyl]oxy}-6-methyl-2-oxopyridin-1(2H)-yl]-4-methylbenzoate trifluoroacetate (from Step 2) (0.50 g, 0.95 mmol) in DMA (4 mL) was added 4-methylmorpholine (0.21 mL, 1.9 mmol) and methyl chloroformate (0.08 mL, 1.0 mmol). Reaction was stirred at RT for 1 h. Solvent removed by distillation. Crude product purified by preparatory HPLC. Acetonitrile was evaporated and the solution washed with 5% NaHCO3 (30 mL) and extracted in DCM (3×25 mL). The organic extracts were dried over Na2SO4, filtered, and concentrated to a white solid, dried in vacuo (0.36 g, 81%). 1H NMR (CD3OD/400 MHz) δ8.03 (m, 1H), 7.77 (s, 1H), 7.53 (d, 1H, J=7.6 Hz), 7.47 (m, 1H), 7.12 (m, 1H), 7.03 (m, 1H), 6.21 (s, 1H), 6.08 (s, 1H), 5.18 (s, 2H), 4.38 (s, 2H), 3.89 (s, 3H), 3.65 (s, 3H), 2.12 (s, 3H), 1.89 (s, 3H). ESHRMS m/z 469.1767 (M+H calculated for C25H26FN2O6 requires 469.1769).
