C([O:3][C:4]([C:6]1[C:7]([CH2:30][N:31]2[CH:35]=[N:34][CH:33]=[N:32]2)=[N:8][C:9]2[C:14]([C:15]=1[C:16]1[CH:21]=[CH:20][C:19]([O:22][CH3:23])=[C:18]([O:24][CH3:25])[CH:17]=1)=[CH:13][C:12]([O:26][CH3:27])=[C:11]([O:28][CH3:29])[CH:10]=2)=[O:5])C.[OH-].[Na+].Cl>C(O)C>[CH3:27][O:26][C:12]1[CH:13]=[C:14]2[C:9](=[CH:10][C:11]=1[O:28][CH3:29])[N:8]=[C:7]([CH2:30][N:31]1[CH:35]=[N:34][CH:33]=[N:32]1)[C:6]([C:4]([OH:5])=[O:3])=[C:15]2[C:16]1[CH:21]=[CH:20][C:19]([O:22][CH3:23])=[C:18]([O:24][CH3:25])[CH:17]=1A mixture of 6,7-dimethoxy-4-(3,4-dimethoxyphenyl)-2-(1,2,4-triazol-1-ylmethyl)quinoline-3-carboxylic acid ethyl ester (3.0 g), 2N sodium hydroxide (15.6 ml) and ethanol (50 ml) was stirred under refluxing conditions for 8 hours. The reaction mixture was cooled with ice and adjusted to pH 5 with 2N hydrochloric acid, after which it was concentrated under reduced pressure. The residue was dissolved in ethanol, and the insoluble substances were filtered off. After the filtrate was concentrated, the residual oily substance was subjected to silica gel column chromatography and eluted with chloroform-methanol (4:1, v/v) to yield 6,7-dimethoxy-4-(3,4-dimethoxyphenyl)-2-(1,2,4-triazol- 1-ylmethyl)quinoline-3-carboxylic acid (1.3 g, 46%), which was then recrystallized from dichloromethane-ethanol to yield a colorless prismatic crystal having a melting point of 270° to 271° C. (decomposed).
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