反应详情

28.6 g of methyl 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 for 40 minutes at 100-110° C. The resulting mixture was cooled and filtered. The precipitate was re-crystallized from choroform-ethanol to afford 25.2 g of 1-cyclopropyl-7-chloro-6-fluoro-8-methoxy-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (Gaticarboxylic acid, 0.081 mol) in 91.8% yield, mp 195-199° C.

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