Observations on the preparation of diaminoguanidine

Diaminoguanidine is a useful intermediate for the production of diheterocyclic systems, e.g. of the 5-aryl- or 5-alkyl-2-tetrazoyl-tetrazole, or the dipyrazoyl-formimine, types. Investigation of existing methods of the preparation of this substituted hydrazine has revealed some hitherto unobserved facts; e.g. (i) preliminary reduction of nitroaminoguanidine to the diaminoguanidine salt, followed by in situ dehydration and cyclization, provides a new route to the alkylaminoiminotriazoles; (ii) hydrazinolysis of the diaminoguanidine hydrazones has been found to take place readily; (iii) although cyanogen chloride and bromide form diaminoguanidine salts with hydrazine hydrate, cyanogen iodide forms an unstable hydrazine complex, without the formation of diaminoguanidine.