ethyl 1-ethyl-7-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylate

ethyl 1-cyclopropyl-7-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate

1-ethyl-7-hydroxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid

7-amino-1-ethyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid