反应详情

To ethyl 7-(1-piperazinyl)-1-cyclopropyl-6-fluoro-5-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylate (23 mg) are added 10% aqueous solution of sodium hydroxide (3 ml) and ethanol (3 ml), and the mixture is refluxed for 1 hour. After cooling, the reaction mixture is diluted with water and washed with dichloromethane. After the aqueous layer is made acidic with acetic acid and then made weak alkaline with an aqueous sodium hydrogen carbonate. The resultant is extracted with dichloromethane and the extract is dried. The solvent is distilled off under reduced pressure and to the residue is added ethanol. The precipitated crystals are filtered and recrystallized from dimethylformamide to give 7-(1-piperazinyl)-1-cyclopropyl-6-fluoro-5-methyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (12 mg), as white powder, m.p. 231°-233° C.

1. temperaturethe mixture is refluxed for 1 hour
2. temperatureAfter cooling
3. washwashed with dichloromethane
4. extractionThe resultant is extracted with dichloromethane
5. customthe extract is dried
6. distillationThe solvent is distilled off under reduced pressure and to the residue
7. additionis added ethanol
8. filtrationThe precipitated crystals are filtered
9. customrecrystallized from dimethylformamide