The thermal decomposition of tetrazoles

A brief review of the literature on the thermal decomposition of chemical compounds containing a tetrazole heterocycle is given. It is shown that there are two radically different pathways of the tetrazole cycle fragmentation connected with the formation of a molecule of nitrogen or azides. The elimination of nitrogen from 2,5-disubstituted tetrazoles results in a nitrilimine. The elimination of nitrogen from 1,5-disubstituted tetrazoles leads to the formation of a nitrene. The stabilization of active intermediate products depends on the chemical properties of the substituents and the conditions under which the process is carried out, and leads to a wide spectrum of final products for the thermal decomposition of tetrazoles. Kinetic studies of the thermolysis of tetrazoles show that the mechanism of heterocycle fragmentation can vary with varying temperature. The elimination of nitrogen from tetrazoles is preceded by a high-polarity transition state.