反应详情

A mixture of ethyl 7-fluoro-1-[2-(S)-fluoro-1-(R)-cyclopropyl]-1,4-dihydro-4-oxoquinoline-3-carboxylate (4.08 g, 13.9 mmol), acetic acid (9 ml) and concentrated hydrochloric acid (9 ml) was heated under reflux for 21 hour. After cooling the reaction solution with ice, ice water (50 ml) was poured into the reaction solution, the precipitated crystals were filtered out, and after washing with excess water, a small amount of cold ethanol and excess diethyl ether, the crystals were dried under a reduced pressure at 80° C. for 16 hours. 3.51 g (95%) of the title compound was thereby obtained in the form of a white powder.

1. temperaturewas heated
2. temperatureunder reflux for 21 hour
3. additionwas poured into the reaction solution
4. filtrationthe precipitated crystals were filtered out
5. washafter washing with excess water
6. dry with materiala small amount of cold ethanol and excess diethyl ether, the crystals were dried under a reduced pressure at 80° C. for 16 hours