Oxirane reactions with triazoles

The reaction of 5-bromo-3-nitro-l,2,4-triazole and 3,5-dinitro-l,2,4-triazole with a variety of oxiranes yielded the expected 1-substituted imidazoles, and also resulted in the formation of 5,6-dihydrooxazolo[3,2-6]-s-triazoles upon treatment with base (75CHE612). The proposed pathway involves proton abstraction from the imidazole and subsequent attack of the oxirane on the N-anion followed by cyclization in a concerted fashion (equation 56). 2,4(5)-Dinitroimidazole reacts analogously with oxiranes to give isomeric nitro-imidazo[2,1 -f>]oxazoles in good overall yield (8UMC601). 

The additive reaction of oxiranes was also utilized for the preparation of SMP networks with covalent crosslinks. The crosslinking of 3-amino-1,2,4-triazole with epoxidized natural rubber catalyzed by bisphenol-A resulted in polymer networks having shape-memory capability with Ti ms = Tg [82]. The Tg could be controlled by the 3-amino-1,2,4-triazole content in the range between 29 and 64 °C. Recently, the crosslinking reaction of oxiranes and amines was systematically investigated in two polymer systems based on the reaction of the diglycidyl ether of bisphenol A epoxy monomer cured with the bifunctional poly(propylene glycol)bis(2-aminopropyl)... 

Low yields of a mixture of cis- and trons-acetylenic thiirans (18) were obtained by treatment of lithium salts of 2-propargylthiothiazolines (17) with benzaldehyde. A mechanism was proposed. Thiiran was proposed as a product, although not identified, in the reaction of oxiran with 3-/3-hydroxyethylthio-1,2,4-triazoles (19) to yield N-/3-hydroxyethyltriazo-linones (20). ... 

---