Transition Metals Revert the Quinolinquinone Reactivity.

Pyridophenoxazinone system, an iminoquinonic planar four-annulated chromophore, recognizes the site-specific sequence Guanine-Cytosine and stabilizes the DNA/drug complex throughstaking interactions and H-bonds.a To synthesize these compounds a reaction between quinolinquinone (QQ) and o-aminophenol (AP) has already been described.b Here we report the results of an ab initio study of QQ vs QQ/Zn complex in the formation of two isomeric 5H-pyridophenoxazin-5-ones. The AP NH2 group attacks the C-6 position of QQ according to the standard QQ reactivity whereas it attacks the C-7 position of the QQ/Zn, QQ/Co, QQ/Cu complexes yielding the 3,2-a and 2,3-a isomers of 5H-pyridophenoxazin-5-one, respectively