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In chemistry, azoxy compounds are a group of sharing a common functional group with the general structure . They are considered Amine oxide of . Azoxy compounds are 1,3-dipoles and cycloadd to double bonds. Most azoxy-containing compounds have aryl substituents.
Nitrosocarbamate decarboxylate in strong base to an azotate susceptible to strong alkylation agents:
An alternative route involves oxidation of with .
trans-Azoxydibenzene's resonance form with a negative formal charge on oxygen (–N=N+(O−)–) corresponds to a theoretical 6Debye dipole moment. However, the observed moment is only 4.7 D, suggesting a substantial resonance contribution in which the other nitrogen bears negative charge (–N−–N+(=O)–).
Unlike , azoxy compounds do not fragment thermally to lose nitrous oxide; the process is believed selection rule. Correspondingly, the reaction is possible under UV light with wavelength approximately 220 nm.
The azoxy group is electron-withdrawing, but in non-oxidizing media, aliphatic locant hydrogens must be situated between two azoxy groups to appreciably dissociate. Alkyllithia replace the hydrogens, but with reduction:
Azoxyarenes ortho to a benzylic carbon with good leaving group eliminate the leaving group to give an indazolone (the Davis-Beirut reaction).
Azoxy compounds are weak bases, and unstable to strong acids. Azoxyarenes undergo the Wallach rearrangement to para-azophenols; primary and secondary azoxyaliphates tautomerize to a hydrazide.
The two aryl groups in azoxyarenes undergo electrophilic aromatic substitution differently. In the case of azoxybenzene, PhNN(O)– reacts at the meta position, while PhN(O)N– reacts at the ortho and para positions.
Electrochemical reduction converts azoxyarenes to azo compounds. Single-electron reductants give a deep-blue radical anion, which dimerizes in aqueous solution to the corresponding azo compound and hydrogen peroxide. Strong reducing agents such as lithium aluminum hydride also hydrogenolysis electronegative ortho or para arene substituents, but catalytic hydrogenation selects out the azoxy link. Conversely, sodium borohydride preserves the azoxy group even as it reduces arene substituents.
(1975). 9780471669241, John Wiley & Sons, Ltd. ISBN 9780471669241
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