[Cl:1][C:2]1[C:3]([F:26])=[CH:4][C:5]2[C:6]([CH:25]=1)=[N:7][C:8]1[N:9]([CH2:21][O:22][CH2:23][CH3:24])[CH:10]=[C:11]([C:16]([O:18]CC)=[O:17])[C:12](=[O:15])[C:13]=1[CH:14]=2>O.C(O)C.[OH-].[K+]>[Cl:1][C:2]1[C:3]([F:26])=[CH:4][C:5]2[C:6]([CH:25]=1)=[N:7][C:8]1[N:9]([CH2:21][O:22][CH2:23][CH3:24])[CH:10]=[C:11]([C:16]([OH:18])=[O:17])[C:12](=[O:15])[C:13]=1[CH:14]=2A suspension of 6 g of 8-chloro-3-ethoxycarbonyl-1-ethoxymethyl-7-fluoro-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine in 120 cm3 of water, 120 cm3 of ethanol and 47.5 cm3 of 2N aqueous potassium hydroxide solution is heated, with stirring, at a temperature close to 75° C. for 2 hours and a half. A small amount of insoluble matter is removed by filtering at the same temperature. After cooling to about 20° C., 6 cm3 of acetic acid are added to the filtrate. The precipitate obtained is drained, washed with 3 times 20 cm3 of water and recrystallized from 60 cm3 of dimethylformamide. 4 g of 8-chloro-1-ethoxymethyl-7-fluoro-4-oxo-1,4-dihydro-benzo[b][1,8]naphthyridine-3-carboxylic acid are obtained in the form of a yellow solid which decomposes at 285° C.
Wird geladen…
