The Wallach Rearrangement. I. The Behavior of 4-Substituted Azoxybenzenes in Strongly Acidic Solution

Abstract

The rearrangement reaction of azoxybenzenes into hydroxyazobenzenes in strongly acidic solution has been studied by an U. V. spectrophotometric method and by isolation of the rearranged compound. In all cases under investigation, it appeared that the oxygen atom in the azoxy group migrated to the unsubstituted ring, depending neither on the substituent already present in the other ring, nor on the distance between the oxygen atom and the eligible position; whereas, the position in the open ring, ortho or para, to which the oxygen migrates depends on the substituent already present in the other ring. In all compounds besides -and -4-methyl azoxybenzene, the oxygen atom migrates to the para position. In the case of and -4-methylazoxybenzene, the oxygen atom migrates to the ortho position of the unsubstituted ring.