Hydrochloric Acid → 2-(5,7-Difluoroquinolin-6-yl)acetic acid

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Reaction Steps

To a round-bottom flask containing 2-(5,7-difluoro-quinolin-6-yl)-malonic acid diethyl ester (2.48 g, 7.68 mmol) were added ethanol (77 mL) and 10% aqueous NaOH (103.2 mL). The solution was refluxed for 3 h. After such time the ethanol was removed under reduced pressure to form a yellow suspension and tetrahydrofuran (50 mL) was added to give a clear yellow solution which was placed in an ice bath and stirred. 6N Hydrochloric acid (50 ml) was slowly added to the solution to reach pH 1. The light orange solution was refluxed for another hour, at which time two layers formed. The top tetrahydrofuran layer was collected and the aqueous solution was extracted with dichloromethane. The organic layers were brined and dried with anhydrous sodium sulfate. The solution was then filtered and the filtrate was concentrated to obtain the title compound (1.20 g, 70.1%). 1H NMR (300 MHz, DMSO-d6) δ 12.82 (s, 1H), 8.98˜9.00 (m, 1H), 8.47˜8.50 (d, 1H), 7.61˜7.74 (m, 2H), 3.86 (s, 2H). ES-MS m/z: 224.2 (M++1).

Provenance & Evidence