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

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Reaction Conditions

Reaction Steps

Neat diethyl malonate (18.05 g, 112.7 mmol) was added slowly to a suspension of sodium hydride (60% in mineral oil, 4.96 mg, 124 mmol) in dimethylacetamide under N2 atmosphere. The mixture was stirred at room temperature until the evolution of hydrogen gas ceased, then the mixture was heated to 90° C. for 30 min. and cooled to room temperature. A solution of isatoic anhydride (20 g, 124 mmol) in dimethylacetamide was added slowly and the mixture heated overnight at 110° C. The mixture was cooled to room temperature, poured into ice water, and acidified by cold 10% HCl. The solids formed were filtered and washed several times by water to yield 8.7 g (30%) of white solids. M.P. 173° C. 1H NMR (DMSO-d6): δ 1.31 (t, J=6.6 Hz, 3H), 4.34 (q, J=6.6 Hz, 2H), 7.20 (t, J=8.0 Hz, 1H), 7.27 (d, J=8.4 Hz, 1H), 7.62 (t, J=7.2 Hz, 1H), 7.93 (d, J=8.0 Hz, 1H), 11.50 (b, 1H); EIMS: 234 (M+H).

Provenance & Evidence