Nitronate structures general reactivity

Compounds of structures (14)-(16) are in general less studied than all other classes of (oxa/thia)-2-azoles, either because of difficulty in their preparation or their thermal instability. Some of them are stable, but others are nonisolable reactive intermediates <75S205). The dioxazolidine (137) is reversibly dissociated to the nitrone and pivalaldehyde <80JCR(S)122> (Equation (2)) the dioxazolidine (138) is more stable, but decomposes on heating at 300°C to yield the pivalaldehyde (Bu CH=0) and the benzimidazolone (139) (Equation (3)) <86JOC732). 

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