Lithium Hydroxide → 3-Cyano-4-(2-methylpiperidin-1-yl)benzoic acid

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2-Methylpiperidine (2.38 mL; 20.29 mmol) was added to a solution of methyl 3-cyano-4-fluorobenzoate, prepared as described in J. Med. Chem. 2004, 47, 1339-1350 from 2-fluoro-5-formylbenzonitrile (727 mg; 4.06 mmol) in DMF (4 mL). The resulting mixture was stirred at RT for 2 days. The solution was partitioned between EtOAc and water and the phases separated. The organic layer was washed with HCl (0.1 M) and brine, dried over MgSO4. Evaporation under reduced pressure afforded a greenish oil. The latter was taken up in THF (10 mL), LiOH (340 mg; 8.12 mmol) and water (10 mL) were added and the reaction mixture was stirred at RT for 16 hours. The resulting solution was diluted with water and washed with Et2O. The aqueous layer was made acidic (pH 2) by addition of HCl (1M) and extracted with EtOAc. The organic phase was dried over MgSO4 and concentrated in vacuo to give a light yellow oil that precipitated upon trituration with a mixture of EtOAc and n-pentane to give the title compound as an off-white solid. 1H NMR (DMSO-d6) δ 13 (br s, 1H), 8.08 (d, J=2.1 Hz, 1H), 8.01 (dd, J=8.8, 2.1 Hz, 1H), 7.18 (d, J=8.9 Hz, 1H), 4.12-4.08 (m, 1H), 3.35-3.25 (m, 2H), 1.84-1.53 (m, 6H), 1.09 (d, J=6.6 Hz, 3H). LC/MS (Method B): 243.2 (M−H)−; 245.2 (M+H)+.

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