Mononuclear heterocyclic rearrangements. Effect of the structure of the side chain on the reactivity. Part 3. Rearrangement of some N-(5-phenyl-1,2,4-oxadiazol-3-yl)- N′-arylformamidines into 1-aryl-3-benzoylamino-1,2,4-triazoles in acetonitrile in the presence of triethylamine

Abstract

The apparent pseudo-first-order rate constants for the title reaction give a curvilinear plot versus tertiary amine concentration, according to the equation k A  ( k u, + K 1 k 2[TEA])/(1 + K 1[TEA]). This shows the occurrence of two different reaction pathways; the one, independent of [TEA] and the other, dependent on [TEA], which involves a fast conversion of the substrate into an acid-base adduct or an ion pair followed by its slow conversion into the corresponding triazole. The substituent effects on these reactions have also been studied.