Formation of dihydrotriphenodioxazines and dihydroisotriphenodioxazines by acidic treatment of some substituted 3H-phenoxazin-3-ones; isolation and characterization. A new perspective in the chemistry of ommochromes
The equilibrium mixture of 2-phenylamino-5-methoxy-1·4-benzoquinones and semiketals, which depends on the substitution of the components and on the solvent, reacts with o-aminophenols in acetic acid to give triphendioxazines. The synthesis unequivocally proves the structure