2.4- Dinitroimidazole, reaction with oxiranes

Analogous reactions of 2,4-dinitroimidazole 38 with oxiranes gave mixtures of the major opened products 39 and minor 2,3-dihydroimidazo[2,l-Z ]oxazoles 40 (79JHC1499, 79JMC583, 84IJC(B)363). Similar behavior was also described... 

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). 

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