Cyanogen azide decomposition

The photolytic and thermolytic decomposition of azides in the presence of olefins has been applied to aziridine synthesis. However, only a limited number of steroid aziridines have been prepared in this manner. The patent literature reports the use of cyanogen azide at ca. 50° for 24 hours in ethyl acetate for the preparation of an A-nor- and a B-norsteroidal aziridine. The addition is believed to proceed via a triazoline. The reaction of cholest-2-ene with ethyl azidoformate takes place in a nonselective manner to produce a mixture of substances, including C—H insertion products. 

Cyanogen azide reacts with olefins at 0-35° to afford alkyl-idene cyanamides and/or N-cyanoaziridines arising from decomposition of an intermediate unstable triazoline. 54 With norbomadiene the isolated product is N-cyano-3-azatricyclo-[3.2.1.0s-4-M<,]oct-6-ene (58) which is unstable and rearranges into N-cyano-2-azabicycIo[3.2.1]octa-3,6-diene (59).167... 

Cyanogen azide is an abundant source of the spectroscopically interesting symmetric cyanonitrene N=G=N . Both the thermal and the photolytic decomposition of N3CN lead to singlet excited nitrenes, as evidenced by stereospecific interception and by spectroscopy. The singlet nitrene decays subsequendy to the triplet ground state of the species . 

Cyanogen azide (NCN3) is another special case, and is notoriously unstable, decomposing at about 50 °C. This facile decomposition is probably due to the unique nature of cyanonitrene - a symmetrical highly stabihzed triplet species (Figure 6.5). 

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