To a solution of 5-benzyloxy-3,4-difluoro-2-((2-fluorophenyl)amino)benzoic acid (19.17 g, 51.35 mmol) in DMF (30 mL) was added potassium bicarbonate (6.16 g, 61.62 mmol) followed by benzyl bromide (6.2 mL, 51.41 mmol). The mixture was stirred for 5 h at room temperature and then water (150 mL) was added. The solution was extracted with ethyl acetate (150 mL×3). The combined organic extracts were washed with water (100 mL×3) and brine (200 mL) sequentially, dried over Na2SO4, filtered and concentrated in vacuo to afford the corresponding product (21.42 g, 90% yield). 1H NMR (400 MHz, CDCl3): δ 8.51 (s, 1H), 7.51 (dd, J=8.5, 2.1 Hz, 1H), 7.46-7.36 (m, 10H), 7.12-7.06 (m, 1H), 7.03 (m, 1H), 6.94 (m, 1H), 6.85 (m, 1H), 5.33 (s, 2H), 5.15 (s, 2H).
