.1 - Ethyl -7 - Chloro - 6 - Fluoro-1 ,4 - Dihydro-4 - Oxo-quinoline 3 - Carboxylic Acid Synthesis Process Optimization

The present developement, antibacterial activity and security of quionlones antibiotics was introduced at first. In this paper we illuminated the synthetic route and antibacterial activity of 7-chloro-l-ethyl-6-fluoro-l,4-dihydro-4-oxoquinoline-3-carb oxylic acid and its derivatives, such as norfloxacin. 7-chloro-l-ethyl-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid was synthesized from 3-chloro-4-fluoro aniline as the starting materials visa condensation with diethyl ethoxymethylene-malonyl, Gould-Jacobs cyclization, ethylation, hydrolysis four steps reaction. The optimum reaction conditions were obtained by experiments, so the yield of product was increased . we use triethyl phosphate as ethylation reagent in the synthesis of 7-chloro-l-ethyl-6-fluoro-1,4- dihydro-4-oxoquinoline-3-carboxylic acid, which was first reported . In the experiment we ditectly use triethyl phosphate as reaction solvent , which made the product very easy to purify. At last , the compounds were detemined with Melting point , IR, ~1H-NMR and MS .