73970-97-5

Upstream product

• 763-29-1 2-Methyl-1-pentene 
• 4233-33-4 4-Phenyl-1,2,4-triazolidine-3,5-dione 

Relevant academic research and scientific papers

Isotope effects and the mechanism of triazolinedione ene reactions. Aziridinium imides are innocent bystanders

Kinetic isotope effects were determined for the ene reactions of 4-phenyl-1,2,4-triazoline-2,5-dione with 2-methyl-2-butene and 2-methyl-1-pentene. In each case highly inverse (kH/kD = 0.87-0.88) vinylic deuterium isotope effects were observed. Large 13C isotope effects were observed for the less-substituted olefinic carbons of each alkene and much smaller effects were found in the more-substituted olefinic carbon. Becke3LYP calculations of the mechanistic pathway for the ene reaction of 1,2,4-triazoline-2,5-dione with isobutene, 2-methyl-2-butene, and tetramethylethylene predict a new mechanism for these reactions involving an open biradical as the key intermediate. This biradical may either form the ene product or reversibly form an intermediate aziridinium imide. The validity of these calculations is supported by a comparison of experimental and theoretically predicted isotope effects. A curved Arrhenius plot of product ratios was found for the ene reaction of 2-methyl-1-pentene in the presence of methanol. This is inconsistent with a simple two-step ene mechanism involving only an aziridinium imide intermediate, but the curvature of this plot could be modeled well by the theoretical mechanism using enthalpy and entropy parameters close to theoretically predicted values. A variety of observations associated with these reactions are examined and found to support the new mechanism.

Ene Reaction of Triazolinediones with Alkenes. 2. Kinetics and Substituent Effects

The kinetic measurements for the reaction of 4-substituted-1,2,4-triazoline-3,5-diones (4-R-TD; R=Ph, Me, p-MeOC6H4, p-NO2C6H4) with alkenes have been undertaken.The reactivity of alkenes was found to be very sensitive to substituent effects.The effects of solvent and substituent on TD were small.In the reaction of TD with ene products, side reactions as well as second-step ene reactions were observed.The reactions of 1-alkyl-4-phenyl-1,2,4-triazolidine-3,5-diones were investigated, and the reaction products were isolated.

Ene Reaction of Triazolinediones with Alkenes. 1. Structure and Properties of Products

The structures of ene products from reaction of triazolinediones with alkenes and polyisoprene were studied by using (1)H NMR.The pKa values of the ene products were measured.The reactivity and stability of the ene products were also studied.