Nitroso compound dimers compounds, review

Nitrosochlorination of alkenes, review 23, 537 suppl. 24 Nitroso compound dimers s. Azo N,N -dioxides... 

A more recent kinetic study has indicated that under acidic conditions a-ketonitrosoalkanes may rearrange rapidly to the oxime [33]. Amines also bring about the isomerization of nitrosocyclohexane [34], These observations along with the older observations mentioned in Touster s review [2] imply that the whole question of the nitrosation of aliphatic carbon atoms should be reexamined with modern techniques to establish the reaction conditions under which the true aliphatic nitroso compounds (or their dimers) can be isolated. 

The nitrosation of aliphatic carbon atoms, particularly of carbon atoms activated by adjacent carbonyl, carboxyl, nitrile, or nitro groups, has been reviewed in great detail [2]. Judging from this review, with few exceptions, nitrosation of active methylene compounds leads to the formation of oximes (unfortunately termed isonitroso compounds in the older literature). The few exceptional cases cited in which true nitroso compounds (or their dimers) were formed involved tertiary carbon atoms in which no hydrogen atoms were available to permit tautomerism to the oxime or involved a reaction which was carried out under neither acidic nor basic conditions. 

The nitrosochlorination of alkenes has been reviewed.146 The products of nitrosochlorination are often dimers due to the propensity of nitroso groups to couple with one another. For this reason, and because of the advent of newer reagents, modem synthetic uses of NOC1 are scarce. Instances where NOC1 has proven to be a useful reagent include the preparation of a-oximinocarbonyl compounds (Scheme 71)147 and the synthesis of precursors of insect growth regulators (Scheme 72).148... 

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