G. Vassilikogiannakis et al., MECHANISTIC STUDIES IN THE REACTION OF 4-PHENYL-1,2,4-TRIAZOLINE-3,5-DIONE WITH 2,5-DIMETHYL-2,4-HEXADIENE, Journal of heterocyclic chemistry, 33(3), 1996, pp. 993-995
Secondary isotope effect measurements of methanol adducts from the rea
ction of 4-phenyl-1,2,4-triazoline-3,5-dione with 2,5-dimethyl-2,4-hex
adiene, support the formation of an aziridinium imide intermediate rat
her than an open dipolar intermediate in the rate determining step.