derivatives of tert-butyl and tert-amyl hydroperoxides were obtained in reactions of azo acid chlorides with hydroperoxides in the presence of an inorganic base. Obtained azo-peresters possess two kinds of the labile functional groups: the azo group and also the perester group. The data from DSC experiments indicate that in the case of azo-perester derivatives of tert-amyl hydroperoxide, the perester group