Mononuclear heterocyclic rearrangements. Part 12. Kinetic study of substituent effects on the rearrangement of the (Z)-phenylhydrazones of some 5-aryl-3-benzoyl-1,2,4-oxidiazoles into 4-aroylamino-2,5-diphenyl-1,2,3-triazoles in dioxane–water at various pS+ values

Abstract

The kinetics of the title reaction have been studied in the pS⁺ range 4.0–12.0, at various temperatures. The logarithmic kinetic constants show excellent linear free energy correlations with σ and σⁿ for the pS⁺- independent and pS⁺-dependent ranges, respectively. The susceptibility constants obtained (p+0.85 and +1.75, at pS⁺ 4.50 and 10.00, respectively) show that a larger negative charge is developed in the transition state of the base-catalysed reaction pathway than in that of the uncatalysed, pS⁺-independent route.