Azoxy

The structure of the azoxy functional group, where R is a substituent.

Azoxybenzene - An example azoxy compound.

Azoxy compounds are a group of chemical compounds sharing a common functional group with the general structure RN=N⁺(O⁻)R.^[1] They are considered N-oxides of azo compounds. Azoxy compounds are 1,3-dipoles. They undergo 1,3 dipolar cycloaddition with double bonds.

Preparation

Most azoxy-containing compounds have aryl substituents. They are typically prepared by reduction of nitrocompounds, such as the reduction of nitrobenzene with arsenous oxide.^[2] Such reactions are proposed to proceed via the intermediacy of the hydroxylamine and nitroso compounds, e.g. phenylhydroxylamine and nitrosobenzene:

PhNHOH + PhNO → PhN(O)NPh + H₂O

Safety

Alkyl azoxy compounds, e.g. azoxymethane are suspected to be genotoxic.^[3]

References

1. IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version:  (2006–) "azoxy compounds".
2. H. E. Bigelow and Albert Palmer "Azoybenzene" Org. Synth. 1931, 11, 16. doi:10.15227/orgsyn.011.0016
3. Guideline On The Limits Of Genotoxic Impurities