SUBSTITUENT EFFECTS IN THE REARRANGEMENT OF 4-ALKYL-4H-1,2,4-TRIAZOLES

A study of the thermal rearrangement of neat 4-alkyl-substituted 4H-1, 2,4-triazoles to the corresponding 1-alkyl-1H-1,2,4-triazoles showed t hat the rearrangement was accompanied by formation of 3,5-diphenyl-1H- 1,2,4-triazole and alkenes. The composition of the product mixture dep ended on the nature of the 4-alkyl group. More branched alkyl groups c aused more elimination. The data were best rationalized by assuming an initial nucleophilic bimolecular activation step where two triazole m olecules formed a dialkyltriazolium triazolate salt. A subsequent reac tion of this salt with a triazole nucleophile/base yielded the rearran gement and elimination products.