反应详情

29.4 g of ethyl 1-cyclopropyl-7-chloro-6-fluoro-8-methoxy-1,4-dihydro-4-oxo-3-quinolinecarboxylate (0.088 mol), 160 ml of acetate acid, 100 ml of water and 18 ml of concentrated sulfuric acid were stirred at 100-110° C. for 40 minutes. The resulting mixture was cooled and filtered. The precipitate was re-crystallized from chloroform-ethanol to give 23.8 g of 1-cyclopropyl-7-chloro-6-fluoro-8-methoxy-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (0.0775 mol) in 88.1% yield, mp 288-293° C.

1. temperatureThe resulting mixture was cooled
2. filtrationfiltered
3. customThe precipitate was re-crystallized from chloroform-ethanol