Hydrochloric Acid → 2,4-Dimethoxyquinoline-3-carboxylic acid

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Reaction Steps

Ethyl 2,4-dimethoxyquinoline-3-carboxylate (1.5 g, 5.7 mmol) was heated at reflux in NaOH solution (10%, 100 mL) for 1 h. After cooling, the mixture was acidified with concentrated HCl to pH 4. The resulting precipitate was collected via filtration and washed with water and ether to give 2,4-dimethoxyquinoline-3-carboxylic acid (A-17) as a white solid (670 mg, 50%). 1H NMR (CDCl3) δ 8.01-8.04 (d, J=12 Hz, 1H), 7.66-7.76 (m, 2H), 7.42-7.47 (t, J=22 Hz, 2H), 4.09 (s, 3H). 3.97 (s, 3H); ESI-MS 234.1 m/z (MH+).

Provenance & Evidence