反应详情

温度

80 °C

1500 g of ethyl 1-cyclopropyl-6,7-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate, 128.4 g of water, and 4500 g of acetic acid were introduced and 53 g of sulfuric acid were added. The mixture was heated at reflux for 4 hours. 2020 ml of distillate were then distilled off until a bottom temperature of 109° C. was reached. The suspension was then cooled to 80° C. and 2204 g of 4% strength by weight sodium acetate solution were added dropwise. The pH was then in the range 3 to 4. The mixture was then cooled to 20° C. and the solid was filtered off with suction. The solid was washed with 2000 ml of water and dried in vacuo at 50° C. 1329 g of 1-cyclopropyl-6,7-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid were isolated, which corresponds to a yield of 98%.

1. temperatureThe mixture was heated
2. temperatureat reflux for 4 hours
3. distillation2020 ml of distillate were then distilled off until a bottom temperature of 109° C.
4. addition2204 g of 4% strength by weight sodium acetate solution were added dropwise
5. temperatureThe mixture was then cooled to 20° C.
6. filtrationthe solid was filtered off with suction
7. washThe solid was washed with 2000 ml of water
8. customdried in vacuo at 50° C