Estimation of Phenols by the 4-Aminoantipyrine Method. II. Products from para-Substituted Alkylphenols

4-Aminoantipyrine reacts with p-alkylphenols on oxidation with potassium ferricyanide to give yellow ortho-quinoneimides. These undergo a thermal and base-catalyzed rearrangement to benzodihydrooxazepines.