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

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

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

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

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