Heterocyclic compounds from urea derivatives. Part X. Addition products of isocyanate esters and diaminoguanidine or its hydrazones, and their cyclisation

Abstract

The condensation of NN′-di(isopropylideneamino)guanidine and aryl isocyanates yields 1-(substituted)-anilinoformyl-2,3-di(isopropylideneamino)guanidines, which are smoothly cyclised in acid media, with loss of arylamine, to 3-hydrazino-5-hydroxy-1,2,4-triazole. The formulation of this triazole is based on its mode of formation, which is parallel to that of its 5-mercapto-analogue of established structure; it is supported by its chemical behaviour, particularly its degradation to authentic 3-hydroxy-1,2,4-triazole.

NN′-Diaminoguanidine reacts additively with one or two moles of isocyanate, to give N-amino-N′-(ω-arylureido)- or NN′-di-(ω-arylureido)-guanidines, respectively, which are isolated as suitable salts. The former, retaining a hydrazino-group in their structure, are capable of yielding derivatives with ketones and β-diketones as expected.