ethyl 6-amino-1-methyl-7-[4-(1,3-thiazol-2-yl)-1-piperazinyl]-4-oxo-1,4-dihydroxyquinolin-3-carboxylate

ethyl 6-amino-1-methyl-4-oxo-7-[4-(2-pyridinyl)-1-piperazinyl]-1,4-dihydro-3-quinolinecarboxylate

6-Amino-1-methyl-4-oxo-7-(2,3,5,6-tetrahydro-[1,2']bipyrazinyl-4-yl)-1,4-dihydro-quinoline-3-carboxylic acid ethyl ester

6-Amino-1-methyl-7-[4-(5-methyl-[1,3,4]thiadiazol-2-yl)-piperazin-1-yl]-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid ethyl ester

6-Amino-7-[4-(2-fluoro-phenyl)-piperazin-1-yl]-1-methyl-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid ethyl ester