1-ethyl-1,2-dihydro-7-methyl-2-oxo-4-(1-piperazinyl)-1,8-naphthyridine-3-carboxylic acid ethyl ester

1-ethyl-1,2-dihydro-7-methyl-4-(4-morpholinyl)-2-oxo-1,8-naphthyridine-3-carboxylic acid ethyl ester

4-diethylamino-1-ethyl-1,2-dihydro-7-methyl-2-oxo-1,8-naphthyridine-3-carboxylic acid ethyl ester

1-ethyl-1,2-dihydro-7-methyl-2-oxo-4-(4-methyl-1-piperazinyl)-1,8-naphthyridine-3-carboxylic acid

1-ethyl-1,2-dihydro-7-methyl-2-oxo-4-(1-pyrrolidinyl)-1,8-naphthyridine-3-carboxylic acid ethyl ester