To a solution of 7-[(4′-trifluoromethyl-biphenyl-2-carbonyl)-amino]-quinoline-3-carboxylic acid ethyl ester (8.45 g, 18.2 mmol, 1 equiv) in MeOH (85 mL) and THF (85 mL) was added 1 N NaOH (91 mL, 91 mmol, 5 equiv). The solution was stirred at room temperature for 4 hours. The organic layer was removed in vacuo and the aqueous layer was washed with EtOAc (100 mL). The aqueous layer was then acidified to a pH of about 4 with concentrated HCl and a precipitate formed. The mixture was stirred for 48 hours and the solids collected by filtration to provide 7-[(4′-trifluoromethyl-biphenyl-2-carbonyl)-amino]-quinoline-3-carboxylic acid (4.5 g, 57% over two steps) as a yellow solid.
