Hydrochloric Acid → 1-(4-Fluorophenyl)-2-oxo-1,2-dihydropyridine-3-carboxylic acid

Participants

Reaction Steps

A mixture of methyl 1-(4-fluorophenyl)-2-oxo-1,2-dihydropyridine-3-carboxylate (crude 2.45 g, 12 mmol) and 6 N aq. NaOH (2.5 mL) in methanol (60 mL) was stirred at rt for 4 h. To the reaction mixture was added conc. HCl (1 mL) slowly with stirring at rt, and the precipitated solid was filtered, washed with a small amount water and dried to obtain the desired acid product (2.1 g, 1st crop) as a yellow solid. The filtrate solution was concentrated in vacuo, and the residue was mixed with water (50 mL), washed with EtOAc (2×130 mL) The organic layers were dried over MgSO4, and concentrated in vacuo. The residue was triturated with a small amount of ether to obtain the 2nd crop of acid product (195 mg, total 2.30 g, 82%). 1H NMR (DMSO-d6) δ 8.47 (dd, 1H, J=7.2, 2.2Hz), 8.19 (dd, 1H, J=6.6, 1.7Hz), 7.62-7.60 (m, 2H), 7.42 (t, 2H, J=8.8 Hz), 6.78 (t, 1H, J=7.1 Hz); MS(ESI+) m/z 234.2 (M+H)+.

Provenance & Evidence