The reaction of ethyl pentafluorobenzoylacetate (I) with ethyl orthoformate in refluxing acetic anhydride and then with cyclopropylamine (II) in ether gives the aminomethylene derivative (III), which is cyclized by means of NaH in THF yielding ethyl 5,6,7,8-tetrafluoro-1-cyclopropyl-4-oxo-1,4-dihydroquinoline-3-carboxylate (IV). The reaction of (IV) with benzylamine (V) by means of K2CO3 in refluxing acetonitrile affords the benzylamino derivative (VI), which is deprotected by hydrogenation with H2 over Pd/C in ethanol giving ethyl 5-amino-1-cyclopropyl-6,7,8-trifluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate (VII). The hydrolysis of (VII) with hot H2SO4 yields the free acid (VIII), which is finally condensed with cis-2,6-dimethylpiperazine (IX) in DMF.

The reaction of ethyl pentafluorobenzoylacetate (I) with ethyl orthoformate in refluxing acetic anhydride and then with cyclopropylamine (II) in ether gives the aminomethylene derivative (III), which is cyclized by means of NaH in THF yielding ethyl 5,6,7,8-tetrafluoro-1-cyclopropyl-4-oxo-1,4-dihydroquinoline-3-carboxylate (IV). The reaction of (IV) with benzylamine (V) by means of K2CO3 in refluxing acetonitrile affords the benzylamino derivative (VI), which is deprotected by hydrogenation with H2 over Pd/C in ethanol giving ethyl 5-amino-1-cyclopropyl-6,7,8-trifluoro-4-oxo-1,4-dihydroquinoline-3-carboxylate (VII). The hydrolysis of (VII) with hot H2SO4 yields the free acid (VIII), which is finally condensed with cis-2,6-dimethylpiperazine (IX) in DMF.