Hydrochloric Acid → 5-Methyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid

Participants

Reaction Steps

Ethyl 5-methyl-4-oxo-1H-quinoline-3-carboxylate (142 mg, 0.61 mmol) was suspended in an aqueous solution of NaOH (1.54 mL of 4% w/v, 1.54 mmol) and the reaction was stirred under reflux for 2 h. After cooling, the reaction mixture was acidified with conc. HCl. The resulting precipitate was collected via filtration, washed with water and dried to yield 5-methyl-4-oxo-1H-quinoline-3-carboxylic acid (42 mg, 34%). 1H NMR (400 MHz, DMSO-d6) δ 15.69 (brs, 1H), 13.81 (brs, 1H), 8.68 (d, J=6.4 Hz, 1H), 7.70-7.64 (m, 2H), 7.27 (d, J=6.4 Hz, 1H), 2.84 (s, 3H). MS (ESI) m/z: 202.2 [M−H]+.

Provenance & Evidence