Triazolines, photodecomposition

Triazoline photodecomposition involving high photoefficiency, insensitivity to solvent and predominant retention of initial geometry in the product constitutes a useful route to aziridines , viz. 

Photodecomposition of A -l,2,3-triazolines gives aziridines. In cyclohexane the cis derivative (304) gives the cis product (305), whereas photolysis in benzene in the presence of benzophenone as sensitizer gives the same ratio of cis- and trans-aziridines from both triazolines and is accounted for in terms of a triplet excited state (70AHC(ll)i). A -Tetrazo-lines are photolyzed to diaziridines. 

Formation of triazoline by addition of phenylazide to 3-methyl-l-butene and its photodecomposition products... 

When, phenylazide and 3-methyl-1-butene are mixed in benzene and kept standing for a couple of days, triazoline is formed and it gives aziridine by thermal or photodecomposition. However, when the mixture is irradiated as soon as they are mixed, the aziridine which is found in the solution is the one formed, not by the decomposition of the triazoline but, by direct photochemical reaction of phenylnitrene with 3-methy1-1-butene. 

Synthesis of triazolines or aziridines from azides by photodecomposition or flash vacuum pyrolysis of 1,2,3-triazolines. 

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