(CAS NO.: ), with other name of , 1,4-dihydro-1-ethyl-6-fluoro-4-oxo-7-(1-piperazinyl)-, could be produced through many synthetic methods.

Following is one of the synthesis routes: 1-Ethyl-6-fluoro-7-chloro-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid (I) is condensed with piperazine (II) to produce Norfloxacin in the condition of heating at 170 C in water in a pressure tube.