Aminotriazoles tautomerism

Treatment of bis(tolylimidoyl) dichloride 358 with 3-aminotriazole (that can exist as two tautomeric structures) affords, after refluxing in THF in the presence of triethylamine, a separable mixture of 5,6-bis-(4-tolylimino)-5//-... 

Similarly, 1,3 -dipolar cycloadditions of benzenesulfonyl azides to N,N- diethylaminoprop-1-yne led to 1,2,3-triazoles (72a) and a-diazoamidines (72b). With the aid of IR and H NMR data these were shown to exist in a tautomeric equilibrium (70JOC3444). With IR and H NMR data a 5-aminotriazole-diazoamidine equilibrium (73a) s (73b) was established (70TL2823, 72CB2963, 72CB2975). However, 4-amino-l,2,3-triazole (74a) proved to be stable and no ring-chain tautomerism could be identified (73TL1137). 

Studies along lines similar to those of this German work, carried out in the United States, led to similar results. In addition, it was shown that 1- N,N-dimethylamino)-2-phenylacetylene gave phenylacetamidines with little tendency to tautomerize to triazoles (70JOC3444). 4-Aminotriazole has been shown not to take part in ring-chain tautomerism (73TL1137). 

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