A mixture of 2-(2-fluoro-5-morpholin-4-yl-phenyl)-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-6-carboxylic acid ethyl ester (0.12 g, 0.29 mmol), lithium hydroxide hydrate (0.12 g, 0.29 mmol), water (2 mL) in methanol (3 mL) and tetrahydrofuran (10 mL) was stirred at 60° C. for 12 h. The mixture was neutralized with a 3 N aqueous hydrochloric acid solution and extracted with ethyl acetate (2×50 mL), washed with water, dried over anhydrous sodium sulfate and then concentrated in vacuo to afford an oil residue. Purification by Waters automated flash system (column: Xterra 30 mm×100 mm, sample manager 2767, pump 2525, detector: ZQ mass and UV 2487, solvent system: acetonitrile and 0.1% formic acid in water) afforded 2-(2-fluoro-5-morpholin-4-yl-phenyl)-3,3-dimethyl-1,2,3,4-tetrahydro-quinoline-6-carboxylic acid (40 mg, 36%) as a white solid: LC/MS m/e calcd for C22H25FN2O3 (M+H)+: 385.5, observed: 385.3.
