To a cooled (−10° C.) solution of 3-[3-bromo-4-[(4-fluoro-2-{[(methoxycarbonyl)amino]methyl}benzyl)oxy]-6-methyl-2-oxopyridin-1(2H)-yl]-4-methylbenzoic acid (0.07 g, 0.13 mmol) in DMF (2.0 mL) was added isobutyl chloroformate (0.02 mL, 0.16 mmol) and 4-methylmorpholine (0.02 mL, 0.16 mmol). After 15 min, 2.0M methylamine in THF (0.01 mL, 0.20 mmol) was added. Solvent removed by distillation after 30 min. 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, concentrated, and dried in vacuo to give a white foam, (0.061 g, 86%). 1H NMR (CD3OD/400 MHz) δ 7.85 (m, 1H), 7.54 (m, 3H), 7.14 (m, 1H), 7.05 (m, 1H), 6.68 (s, 1H), 5.40 (s, 2H), 4.43 (s, 2H), 3.64 (s, 3H), 2.89 (s, 3H), 2.08 (s, 3H), 1.99 (s, 3H). ES HRMS m/z 546.0987 and 548.1018 (M+H calculated for C25H26BrFN3O5 requires 546.1034 and 548.1018).
