1-ethyl-6-fluoro-1,4-dihydro-7-hydroxy-4-oxo-1,8-naphthyridine-3-carboxylic acid

ethyl 7-(4-acetyl-1-piperazinyl)-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate

ethyl 7-chloro-1-ethyl-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate

ethyl 7-(4-acetyl-1-piperazinyl)-1-ethyl-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate

ethyl 7-(4-acetylpiperazin-1-yl)-6-amino-1-ethyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylate