A kinetic study on the base-catalysed E→Z isomerization of some arylhydrazones of 3-benzoyl-5-phenyl-1,2,4-oxadiazole: effect of the substituents in the arylhydrazone moiety
Abstract
The kinetic data obtained in the study of the title reaction reveal unusual substituent effects. A logarithmic plot of reactivity data versus substituent constants (σ and/or σ–) shows a ‘zigzag’ trend; it is suggested that this depends on a changeover of the mechanism and/or of the rate-determining step.