[CH2:1]([O:3][C:4]1[CH:5]=[C:6]2[C:11](=[N:12][C:13]=1[CH3:14])[N:10]=[CH:9][C:8]([C:15]([O:17]CC)=[O:16])=[C:7]2[OH:20])[CH3:2].[OH-].[Na+]>O>[CH2:1]([O:3][C:4]1[CH:5]=[C:6]2[C:11](=[N:12][C:13]=1[CH3:14])[N:10]=[CH:9][C:8]([C:15]([OH:17])=[O:16])=[C:7]2[OH:20])[CH3:2]A mixture of ethyl 6-ethoxy-4-hydroxy-7-methyl-1,8-naphthyridine-3-carboxylate (10.0 g), 5M sodium hydroxide solution (200 ml), IMS (64 ml) and water (64 ml) was boiled under reflux for 2 hours. The mixture was cooled to ambient temperature and then filtered. The residue was dissolved in water, acidified to pH5 with glacial acetic acid and filtered. The residue was triturated with hot IMS, cooled and filtered to give 6-ethoxy-4-hydroxy-7-methyl-1,8-naphthyridine-3-carboxylic acid, m.p. 259°-261° C.
불러오는 중…