2,6-bis{1-ethyl-7-methyl-N-[3-methyl-1-(methylamino)-1-oxobutan-2-yl]-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxamido}pyrrolo[3,4-f]isoindole-1,3,5,7-(2H,6H)-tetrone

1-ethyl-N-(2-hydrazinyl-2-oxoethyl)-7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxamide

1-ethyl-N-(1-hydrazinyl-3-ethyl-1-oxobutan-2-yl)-7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxamide