REACTIVE INTERMEDIATES .8. THERMOLYSIS OF N-(VINYLAZIRIDINYL)-BENZOAXAZOLINONES . SOME NEW HETEROCYCLIC REARRANGEMENTS

Simple 2-vinylaziridines rearrange on heating to 3-pyrrolines. This new rearrangement is structurally analogous to that of vinylcyclopropanes to cyclopentenes but occurs under much milder conditions, probably by a similar homolytic mechanism via a more stable, allylic-hydrazino-diradical. Thermolysis of a more highly methylated vinylaziridine is complex, however, and depends critically upon the pH of the vessel surface. Various 1.5-sigmatropic shifts are proposed to account for the observed products.