To a stirred mixture solution of 3,3-dimethyl-2-(5-morpholin-4-yl-pyridin-3-yl)-1,2,3,4-tetrahydro-quinoline-6-carboxylic acid ethyl ester (2.5 g, 6.5 mmol) in methanol (15.0 mL) and tetrahydrofuran (16.0 mL) was added 50% sodium hydroxide in water (2.0 mL). The reaction mixture was stirred at 70° C. for 6 hours. The mixture was neutralized with a 3 N aqueous hydrochloric acid solution and extracted with ethyl acetate (2×100 mL), washed with water, dried over anhydrous sodium sulfate and then concentrated in vacuo. 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% ammonium hydroxide in water) afforded 3,3-dimethyl-2-(5-morpholin-4-yl-pyridin-3-yl)-1,2,3,4-tetrahydro-quinoline-6-carboxylic acid (2.1 g, 90%) as a white solid: LC/MS m/e calcd for C21H25N3O3 (M+H)+: 368.45, observed: 368.1.
