Sodium Hydroxide → 4-Oxo-5-(trifluoromethyl)-1,4-dihydroquinoline-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

Ethyl 4-oxo-5-(trifluoromethyl)-1H-quinoline-3-carboxylate 6 (58 g, 0.2 mol, crude reaction slurry containing Pd/C) was suspended in NaOH (814 mL of 5 M, 4.1 mol) in a 1-L flask with a reflux condenser and heated at 80° C. for 18 h, followed by further heating at 100° C. for 5 h. The reaction was filtered warm through packed Celite to remove Pd/C and the Celite was rinsed with 1 N NaOH. The filtrate was acidified to about pH 1 to obtain a thick, white precipitate. The precipitate was filtered then rinsed with water and cold acetonitrile. The solid was then dried under vacuum to provide 4-oxo-5-(trifluoromethyl)-1,4-dihydroquinoline-3-carboxylic acid 7 as a white solid (48 g, 92% yield). 1H NMR (400.0 MHz, DMSO-d6) δ 15.26 (s, 1H), 13.66 (s, 1H), 8.98 (s, 1H), 8.13 (dd, J=1.6, 7.8 Hz, 1H), 8.06-7.99 (m, 2H).

Provenance & Evidence