反应详情

5-Amino-1-cyclopropyl-6,8-difluoro-7-(3-methyl-1-piperazinyl)-1,4-dihydro-4-oxoquinoline-3-carboxylic acid was suspended in absolute ethanol. Concentrated sulfuric acid was added to the suspension and the mixture was refluxed for 10 hours with stirring. After evaporation of ethanol, chloroform and a 20% aqueous sodium hydroxide solution were added to the residue, and the mixture was adjusted to pH 9. The organic layer was separated and chloroform was evaporated under reduced pressure. The resulting crystals were collected by filtration to give ethyl 5-amino-1-cyclopropyl-6,8-difluoro-7-(3-methyl-1-piperazinyl)-1,4-dihydro-4-oxoquinoline-3-carboxylate, m.p. 132°-134° C.

1. temperaturethe mixture was refluxed for 10 hours
2. customAfter evaporation of ethanol, chloroform
3. additiona 20% aqueous sodium hydroxide solution were added to the residue
4. customThe organic layer was separated
5. customchloroform was evaporated under reduced pressure
6. filtrationThe resulting crystals were collected by filtration