| 摘要 |
1-Cyclopropyl-6-fluoro 1,4-dihydro 4-oxo -2-(1-piperazinyl) quinoline 3-carboxylic acid of formula (I), with antibacterial properties against numerous pathogens, is made by (a) reaction of 2-ethoxymethylene-3-oxo 3-(2,4-dichloro 5-fluoro phenyl) propionic acid ethyl ester of formula (II), with ammonium hydroxide to give 6-fluoro 7-chloro 4-oxo 1,4-dihydro quinoline 3-carboxylic acid; (b) condensing this with 1-acetyl piperazine in aprotic polar solvent at 100-150 deg.C to obtain 6-fluoro 7-(4-acetyl 1-piperazinyl) quinoline 3-carboxylic acid; (c) reacting with eyelopropyl chloride to form 1-cyclopropyl-6-fluoro 7- (4-acetyl 1-piperazinyl) quinoline 3-carboxylic acid; and (d) hydrolysing this to give (I).
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