Azoxy compounds rearrangement with acid

Aromatic and aliphatic primary amines can be oxidized to the corresponding nitro compounds by peroxy acids and by a number of other reagents. The peroxy acid oxidations probably go by way of intermediate hydroxylamines and nitroso compounds (Scheme 2). Various side reactions can therefore take place, the nature of which depends upon the structure of the starting amine and the reaction conditions. For example, aromatic amines can give azoxy compounds by reaction of nitroso compounds with hy-droxylamine intermediates aliphatic amines can give nitroso dimers or oximes formed by acid-catalyz rearrangement of the intermediate nitrosoalkanes (Scheme 3). 

Rearrangement of Azffxy Compounds (WaUach Rearrangement) The Wallach rearrangement is a reaction that converts an aromatic azoxy compound (170) into an azo compound (174) with sulfuric acid, wherein one ring is substituted by a hydroxyl group in the para position (Scheme 18.27). 

Unsymmetrical azo- or azoxy-compoimds on reduction with tin and hydrochloric add produce a mixture of two amines, while hydrazo-compounds may yield amine(s) formed by normal reduction of the hydrazo-link and a diamine produced by a benzidine rearrangement. Nitro-samines, on reduction with tin and acid, give the secondary amines from which they were derived.)... 

In addition to the detection of the azoxy group in the molecule by the rearrangement of the substance to hydroxyazobenzenes, the N=N bond can be cleaved, as in azo compounds, by an energetic reduction with Zn or SnCl2 in an acid medium (50). 

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