Structural Characterization of a Benzoxazinophenoxazine Formed as a By-Product During the Synthesis of a 3-Amino-N,N-dimethylsalicylamide

Several highly colored by‐products were observed chromatographically during the synthesis of 3‐amino‐N,N‐dimethylsalicylamide. One of these, an oxidative dimerization products, bis‐(N,N‐dimethylcarboxamido)‐aminophenoxazinone, was previously isolated and characterized. A tris‐(N,N‐dimethylcarboxamido)‐benzoxazino[3,2‐b]phenoxazine, presumably a higher oxidation or further reaction product of the previously isolated and characterized 2‐amino‐3H‐phenoxazin‐3‐one, has also been isolated and characterized by mass spectrometry and multinuclear NMR methods. We now wish to communicate the results of that structure characterization effort.