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

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

ethyl 6-amino-7-[4-(4-fluorophenyl)-1-piperazinyl]-1-tert-butyl-4-oxo-1,4-dihydroquinoline-3-carboxylate

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

6-Amino-1-tert-butyl-4-oxo-7-thiomorpholin-4-yl-1,4-dihydro-quinoline-3-carboxylic acid ethyl ester