Hydrochloric Acid → Methyl 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylate

Participants

Reaction Steps

Dimethylmalonate (2.2 mL, 19.2 mmol) was added slowly to a suspension of 60% sodium hydride in mineral oil (0.81 g, 20.3 mmol) in anhydrous DMF (50 mL) at −10° C. under nitrogen. After stirring at room temperature for 30 minutes, isatoic anhydride (3.0 g, 18.4 mmol) was added, and the reaction was heated at 115° C. for 2.5 hours. The reaction was cooled to room temperature, then poured into ice water (500 mL) and acidified to pH 2 with 2M HCl. The resultant precipitate was collected by filtration to give crude methyl 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylate (2.89 g, 72%), which was used without further purification. 1H NMR (400 MHz, DMSO-d6) δ3.86 (s, 3H), 7.23 (m, 2H), 7.63 (m, 1H), 7.94 (dd, J=0.8, 8.0 Hz, 1H), 11.55 (s, 1H), 13.33 (s, 1H). MS 220 (MH+).

Provenance & Evidence