Lithium Hydroxide → 4-Ethoxy-1-(4-fluorophenyl)-2-oxo-1,2-dihydropyridine-3-carboxylic acid

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Reaction Conditions

Reaction Steps

A mixture of ethyl 4-ethoxy-1-(4-fluorophenyl)-2-oxo-1,2-dihydropyridine-3-carboxylate (60 g, 0.196 mol) and LiOH (30 g, 0.6 mol) in EtOH (200 mL) and water (100 mL) was stirred at ambient temp (˜25° C.) for 16 h. The mixture was concentrated to remove EtOH. The residue was diluted with water (300 mL). The mixture was extracted with EtOAc (100 mL) to remove the impurity. The pH was adjusted with 37% HCl to pH<2. The mixture was extracted with EA (3×300 mL). The combined organics were washed with brine, dried over Na2SO4 and concentrated to remove EtOAc. Petroleum ether (PE) (200 mL) was added. The resultant precipitate was collected by filtration, washed with PE and dried to afford 4-ethoxy-1-(4-fluorophenyl)-2-oxo-1,2-dihydropyridine-3-carboxylic acid. (43 g, 78.9% yield). 1H-NMR (400 MHz, DMSO-d4): δ 7.95 (d, J=8.0 Hz, 1H), 7.48 (m, 2H), 7.35 (m, 2H), 6.58 (d, J=7.6 Hz, 1H), 4.28 (q, J=7.2 Hz, 2H), 1.32 (t, J=7.2 Hz, 3H).

Provenance & Evidence