A new synthetic entry to fused azaquinones by a cycloaddition/ring transformation sequence starting from pyrido[1,2-a]pyrazines

Article abstract of DOI:10.1016/S0040-4020(97)00239-1

An expedient one-pot synthesis via a novel cycloaddition/ring transformation sequence allows the introduction of two arylamino groups and a pyridine substructure on azaquinones. Using 1,4-benzoquinone a twofold regioselective reaction yields the deeply blue colored 2,7-diaza-anthraquinones 8, which could be determinated by NMR spectroscopy. In addition, an X-ray structural analysis of the juglone derivative 11 reveals the regioselective arrangement of the bipyridine subunit into the quinone moiety.