A mixture of [4-difluoromethoxy-2-ethyl-8-fluoro-3-(4-fluorobenzyl)quinolin-5-yloxy]acetic acid methyl ester (050 g), methanol (10 mL); tetrahydrofuran (10 mL), water (8 mL) and lithium hydroxide (0.050 g) was stirred at room temperature for 30 minutes. The mixture was partitioned between ethyl acetate and 1.0 M aqueous hydrochloric acid and the aqueous phase was extracted with ethyl acetate. The combined extracts were dried over magnesium sulfate and the solvent removed under reduced pressure. Purification of the residue by preparative reverse-phase HPLC using a gradient over 30 minutes of acetonitrile in water, followed by washing with diethyl ether gave title compound as a white solid, 0.090 g.
