Chemistry of heterocyclic quinoneimines. 9. Reaction of benzo[a]phenoxazin-9-one with C-nucleophiles
Selective replacement of the hydrogen atom in the 5 position of the aromatic fragment of the substrate by the residue of a C-nucleophile, which is accompanied by rearrangement of the benzoquinoid structure to a naphthoquinoid structure, occurs in the reaction of benzo[a]phenoxazin-9-one with cyanoacetic acid derivatives under conditions of activation of the reagent.