The Oxygen Transfer Reaction of 4-Acetylazoxybenzenes in Sulfuric Acid.

When the starting materials 4-acetyl-ONN- and -NNO-azoxybenzene (1alpha and 1beta, respectively) were heated in 70/80% sulfuric acid, alpha/beta isomerization and the Wallach rearrangement to 4-acetyl-4'-hydroxyazobenzene (2) were observed. However, neither the o-hydroxyazobenzene nor 4-acetyl azobenzene was detected in the reaction product. The isomerization of la was faster than that of 1beta, demonstrating the higher themodynamic stability of the latter.