Photolysis of three alkenyl nitrosamines in the presence of oxygen or bromotrichloromethane resulted in the interception of the intermediate C-radicals by these radical trapping agents and the reaction pathways were cleanly diverted leading to the formation of the nitrate esters or halides with pyrrolidine rings as the primary products. The exo-nitrates in the oxidative photolyses decomposed by secondary ionic pathways; these reactions were hydrolysis, nitrous acid elimination and a cleavage reaction (promoted by a β-amino group), among others. The efficiency of the cleavage reaction is controlled by a stereoelectronic factor that requires the participating bonds and the lone-pair nitrogen orbital be oriented in an antiperiplanar conformation. When such a conformation exists in a rigid or semiflexible framework, cleavage occurs extensively. However, in freely rotating acyclic systems, cleavage does not occur even when the required conformation can be attained. Only halides resistant to intramolecular nucleophilic displacement to form the aziridinium intermediates were isolated in the bromotrichloromethane trapping experiments. Other exo-halides underwent solvolysis via aziridinium ion intermediates.

Photolysis of N-nitropiperidine under neutral conditions generates the piperidinyl radical and under acidic conditions the piperidinylium radical, indicated by their addition reaction with cyclohexene.

Conditions necessary for the formation of the (+)3-thujone bisulfite adduct 1a and its utilization for the isolation of pure (+)-thujone have been established.

Photolysis of nitramines in a neutral solvent generated nitrogen dioxide and aminyl radicals which abstracted a hydrogen but did not add to a π-bond. In dilute acidic solution, the aminyl radicals generated from the photolysis were protonated to the corresponding aminium radicals that preferentially added to π-bonds rather than abstracted a hydrogen. However, complex mixtures of addition products were obtained when nitramines were photolysed in the presence of cyclohexene under nitrogen. The plethora of the products is believed to arise from the complex behavior of nitrogen dioxide in solution; for example, (i) nitrogen dioxide may react as O- or N-radical, (ii) nitrogen dioxide exists in equilibrium with nitrogen tetraoxide, and (iii) both oxides can react as oxidizing or radical trapping agents. Under oxygen, the oxidative addition of nitramines to cyclohexene gave 1-dialkylamino-2-nitratocyclohexenes which could be treated with lithium aluminium hydride to give good yields of the corresponding amino alcohols. The quantum yields of nitramine disappearance indicated that the photolysis followed short chain processes either in neutral or acidic conditions. The decrease in quantum yield at >2 N H2SO4 is believed to be due to a reduced reactivity of aminium radicals in a highly acidic environment. The probable mechanisms of these photolytic radical chain processes are discussed.

Nitroethane and higher homologous primary nitroalkanes undergo a base-catalyzed condensation yielding the corresponding 2,3,4-trialkyisoxazoles. Basic hydrolysis of nitroethane to acetaldehyde is the key initial step followed by a series of condensation and elimination reactions. Through the use of appropriately 14C-labelled intermediates and acetaldehyde-d4, a relatively simple mechanism is indicated which will satisfactorily account for all observed intermediates indicated in a summary of the reaction sequence.