phenanthroline(1) was oxidized by a mixture of concentrated sulfuric acid and concentrated nitric acid in the presence of sodium bromide to yield 1,10 phenanthroline 5,6 dione(2) in 90%. Compound 2 gave a mono oxime(3) hydrochloric salt in nearly quantitive amount by reacting with equal molar hydroxylamine hydrochloride. The structures of the compounds were characterized by IR and 1 H NMR spectroscopy. The method is more simple and efficient.
