反应详情

The preparation comprises dissolving Ethyl 1-cyclopropyl-6,7-difluoro-8-methoxy-1,4-dihydro-4-oxoquinoline-3-carboxylate (10.0 g, 30.9 mmol) in 40% HBr aqueous solution (20 mL) and acetic acid (20 mL) to react at 100° C., charging reaction mixture into ice water (500 mL) under fast stirring after the reaction finishes, going on with the stirring for 0.5 h, filtering, and drying obtained filter cake to give 1-cyclopropyl-6,7-difluoro-8-hydroxy-1,4-dihydro-oxoquinoline-3-carboxylic acid (7.8 g, 89.6%).

1. customto react at 100° C.
2. customstirring for 0.5 h
3. filtrationfiltering
4. customdrying
5. customobtained
6. filtrationfilter cake