Standard enthalpies of formation of some N-spiranes

The heats of combustion of three compounds, members of a new series of N-spiranes were measured by combustion calorimetry. The molecules of the title compounds comprise condensed and N-spirofused heterocycles as well as nitroxy groups that are both NO-donors and explosophores. The enthalpies of formation and the heats of explosive transformation of these compounds are calculated. Two compounds belong to explosives with low heat of explosive transformation, whereas the third compound is inert.