A2-Tetrazolines

Photodecomposition of A2-1,2,3-triazolines gives aziridines. In cyclohexane the cis derivative (434) gives the cis product (435), whereas photolysis in benzene in the presence of benzophenone as sensitizer gives the same ratio of cis- and /ran.y-aziridines from both triazolines which is accounted for in terms of a triplet excited state (70AHC(il)l). A2-Tetrazolines are photolyzed to diaziridines. 

IR spectra or trapped by oxalyl chloride or water. Furthermore, the isomeric 1,4-substituted A2-tetrazoline-5-thiones, which would have been formed by C=N instead of C=S addition, were definitively excluded by independent synthesis.64... 

Oxidation of formazans with a wide range of oxidizing agents leads to 2,3-disubstituted tetrazolium salts. Recently, oxidations with cupric acetate and cobalt chloride have led to mixtures of metal-formazan complexes and tetrazolium salts arising from competing reactions in which the balance depended on the substituents present in the formazans.462 Reduction of 1,4,5-trisubstituted tetrazolium iodides with NaBH has been used to prepare A2-tetrazolines.463 A similar attempted reduction of 1,3,5-trisubstituted tetrazolium salts gave no reaction.463... 

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