Azodioxy compounds

The addition of nitrosyl chloride to cyclohexene in sulfur dioxide at low temperature21 -25, or the reaction of cyclohexene with 3-methylbutyl nitrite and hydrochloric acid (producing nitrosyl chloride in situ)25 gave only the tram-adduct 1, isolated in high yield as a crystalline nitroso dimer (azodioxy compound) with E configuration at the N—N double bond. The trans configuration of the chloro and nitroso groups (mixture of diaxial and diequatorial conform-ers) was deduced by IR and H-NMR analyses (a mixture of conformers with both axial and both equatorial substituents is apparent)23-25 and by reduction with lithium aluminum hydride in tetrahydrofuran to yield tram-2-chloro-l-cyclohexanamine (trans-2)23. 

Another method is the reduction of aliphatic azodioxy compounds [81], obtained by addition of nitrosyl chloride to alkenes, to azoxy compounds. 

A previously reported process has been generalized to provide a flexible and directed synthesis of azoxyalkanes (Scheme 130). The Z-E thermal isomerization of aliphatic azodioxy-compounds (dimeric nitroso-alkanes) has been shown to occur exclusively by a dissociation-recombination mechanism. 

Azoxy-Compounds.—NN-Dihaloamines condense with tertiary nitroso-alkanes to give unsymmetrical azoxy compounds in the presence of various promoters e.g., CuCl, CuCN, or KI). Electrolysis of azodioxy compounds in acidic solution gives a good yield of symmetrical azoxy compounds. ... 

In another system recently proposed, the trans isomer of dimeric 1-chloro-2-nitrosocyclohexane would be called Dms-2,2 -dichloro-rra .y-azodioxy-cyclohexane [15,16]. In line with a system used in naming azoxy compounds, the dimers may also be named as diimide dioxides. 

C-nitroso. Following disagreements between earlier studies for nitrosobenzene , Dahn and coworkers measured the of several C-nitroso compounds (see Table 15) and confirmed very low field values in the region of 1530-1550 ppm, among the most shielded values reported so far . Association to give azodioxy dimers led to shifts at much higher field (440 20 ppm). 

As such, a more thorough description of the energetics of nitroso cointounds may well logically appear in a future Patai volume on functional groups devoted to nitrogen-nitrogen bonds such as hydrazo, azo and azoxy compounds, since azodioxy species would seem to belong with these functionalities. We additionally note that these azodioxy species can occur in both cis- and trans-form, and the relative stability seems dependent on the affixed hydrocarbyl moiety. 

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