Dihydrotetrazolium salts

It was shown earlier <1998J(P1)1755> that heteroallene salts with A, A -dialkylcarbodiimides undergo cycloaddition to furnish l,3,4,5-tetrasubstituted-4,5-dihydrotetrazolium salts (cf. Section 6.07.9.3), which on heating in acetonitrile eliminate an alkene to afford 1,3,5-trisubstituted tetrazolium salts. 

The electrode reaction of galactodiphenyltetrazolium salts is affected by the simultaneous occurrence of two processes in which formazane and a dihydrotetrazolium derivative (two-electron stage) are formed. The latter is then converted into hydrazidine (also with the use of two electrons) the contributions of the two mechanisms depend on the pH value p.68]. After irradiation phenyltetrazolium chloride was converted to a free radical by accepting four electrons [169]. Ditetra-zolium compounds [169, 170], formazanes, and tetrazolium derivatives of sugars [171] have also been investigated and the results were summarized [172, 173]. 

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