Potassium Hydroxide → 6-Fluoro-3-methyl-2-[3-(trifluoromethyl)phenyl]-4-quinolinecarboxylic acid

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Reaction Steps

Potassium hydroxide (20.39 g, 363 mmol) in water (40 mL) was added to a suspension of 5-fluoro-1H-indole-2,3-dione (10.0 g, 60.6 mmol) in ethanol (100 mL) slowly. 1-[3-(Trifluoromethyl)phenyl]-1-propanone (12.24 g, 60.6 mmol) was added, and the mixture was heated to reflux for 1 h. The solvent was removed under reduced pressure, the residue was dissolved in water, and the mixture was washed with ether (3 times). The aqueous mixture was chilled and adjusted to pH˜3 with concentrated HCl. The solid was collected by filtration, washed with water, and air dried to afford 6-fluoro-3-methyl-2-[3-(trifluoromethyl)phenyl]-4-quinolinecarboxylic acid (21.2 g, >99% yield). MS (m/z) 350.1 (M+H+).

Provenance & Evidence