Hydrochloric Acid → HCID 136331493, compound

Participants

Reaction Steps

To a solution of 2-carboxy-5,7-dichloro-4-oxo-1,2,3,4-tetrahydroquinoline (Example 1) (14.85 g, 57.1 mmol) in methanol (300 ml) was added hydroxylamine hydrochloride (4.17 g, 60.0 mmol) followed by dry pyridine (4.85 ml, 60.0 mmol) and the resulting mixture was heated at reflux under an atmosphere of nitrogen for 2 hours. The mixture was then cooled, and a solution of methanol saturated with hydrogen chloride (50 ml) was added and the reaction was stirred at room temperature under an atmosphere of nitrogen for 17 hours. The solvent was removed in vacuo and the residue was partitioned between water (300 ml) and diethyl ether (300 ml). The aqueous phase was further extracted with diethyl ether (2×300 ml) and the combined organic layers were washed with 0.5M aqueous citric acid solution (1×200 ml), saturated hydrogen sodium bicarbonate solution (2×200 ml), brine (1×200 ml), then dried (MgSO4) and the solvent was removed under vacuum to give the title compound (15.1 g) as a brown solid (m.p. 216°-217° C.); δ (360 MHz, DMSO) 2.79 (1H, dd, J=15.4 and 6.1 Hz, CHAHBCHC), 3.25 (1H, dd, J=15.4 and 5.8 Hz, CHAHBCHC), 3.64 (3H, s, CO2CH3), 4.23 (1H, m, CHAHBCHC), 6.70 (1H, d, J=2.1 Hz, 6-H or 8-H), 6.82 (1H, d, J=2.1 Hz, 6-H or 8-H), 7.01 (1H, br, s, NH), 11.41 (1H, s, NOH); m/e 288 (M+), 213 (100%); Found: C, 45.75; H, 3.50; N, 9.51; C11H10Cl2N2O3 requires C, 45.70; H, 3.49; N, 9.69%.

Provenance & Evidence