C[C:2](C)([C:6]([O-:8])=[O:7])C([O-])=O.[H-].[Na+].[C:12]12[C:18](=[CH:19][CH:20]=[CH:21][CH:22]=1)[NH:17][C:16](=[O:23])[O:15][C:13]2=O.Cl.[CH3:25]N(C=O)C>>[OH:15][C:13]1[C:12]2[C:18](=[CH:19][CH:20]=[CH:21][CH:22]=2)[NH:17][C:16](=[O:23])[C:2]=1[C:6]([O:8][CH3:25])=[O:7]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) δ 3.86 (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+).
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