Mechanistic studies in the reaction of 4-phenyl-1,2,4-triazoline-3,5-dione with 2,5-dimethyl-2,4-hexadiene

Secondary isotope effect measurements of methanol adducts from the reaction of 4-phenyl-1,2,4-triazoline-3,5-dione with 2,5-dimethyl-2,4-hexadiene, support the formation of an aziridinium imide intermediate rather than an open dipolar intermediate in the rate determining step.