[NH2:1][C:2]1[C:3]([C:14]([OH:16])=[O:15])=[N:4][C:5]2[C:10]([CH:11]=1)=[CH:9][CH:8]=[C:7]([CH:12]=[CH2:13])[CH:6]=2.[OH-].[Na+].Cl[C:20]([O:22][CH2:23][C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1)=[O:21]>O>[CH2:23]([O:22][C:20]([NH:1][C:2]1[C:3]([C:14]([OH:16])=[O:15])=[N:4][C:5]2[C:10]([CH:11]=1)=[CH:9][CH:8]=[C:7]([CH:12]=[CH2:13])[CH:6]=2)=[O:21])[C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1A vial containing the crude 3-amino-7-vinylquinoline-2-carboxylic acid (0.75 g, 3.5 mmol), water (60 mL) and NaOH (7.0 g, 180 mmol) was cooled to −10° C. Benzyl chloroformate (5.0 mL, 33 mmol) was added slowly to the mixture. The mixture was allowed to warm to room temperature and stirred for 1 h. The organic solvent was then removed under reduced pressure. The remaining aqueous layer was neutralized with aq. HCl. The yellow precipitate formed was collected by vacuum filtration, and washed with cold MeOH to give the sub-title compound (1.12 g, 92%) as light yellow powder. LCMS calc. for C20H17N2O4 (M+H)+: m/z=349.1. Found: 349.1.
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