2-Oxobutanoic Acid → 6-Fluoro-3-methyl-7-(methyloxy)-2-[3-(trifluoromethyl)phenyl]-4-quinolinecarboxylic acid

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Reaction Steps

A solution of the 4-fluoro-3-(methyloxy)aniline (11.29 g, 80 mmol) and 3-(trifluoromethyl)benzaldehyde (13.93 g, 80 mmol) in ethanol (200 mL) was heated to reflux for 1 h. 2-Oxobutanoic acid (8.17 g, 80 mmol) was added portionwise. The reaction mixture was stirred at reflux for additional 3 h, cooled to room temperature, and stirred at room temperature overnight. The solid was collected by filtration, washed with ethanol, and air dried to give 6-fluoro-3-methyl-7-(methyloxy)-2-[3-(trifluoromethyl)phenyl]-4-quinolinecarboxylic acid (16.05 g, 53% yield). 1H NMR (400 MHz, DMSO-d6) δ 14.35 (br. s., 1H), 7.93-8.00 (m, 2H), 7.85-7.91 (m, J=7.78 Hz, 1H), 7.74-7.81 (m, 1H), 7.68-7.73 (m, J=8.53 Hz, 1H), 7.54 (d, J=12.05 Hz, 1H), 4.03 (s, 3H), 2.38 (s, 3H); MS (m/z) 380.1 (M+H+).

Provenance & Evidence