反应详情

To a mixture of glacial acetic acid (170 ml) and concentrated hydrochloric acid (170 ml) was added 4.3 g of 1-ethyl-6-fluoro-7-(1-piperazinyl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid ethyl ester and the reaction mixture was concentrated under reduced pressure. The residue was dissolved in 10 ml of water and adjusted to pH 7.5 with diluted sodium hydroxide solution. The precipitated crystals were carried out by the same way in the Example 1 to give 3.3 g (84% yield) of 1-ethyl-6-fluoro-7-(1-piperazinyl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid. mp: 220.5°-222° C.

1. concentrationthe reaction mixture was concentrated under reduced pressure
2. dissolutionThe residue was dissolved in 10 ml of water