ON THE MECHANISM OF INDENO[1,2,3-C,D]PYRENE OZONATION

Calculations on the strongly cancerogenic indeno[1,2,3-c,d]pyrene and all its possible primary and secondary ozonides by the MNDO method ind icate the breaking of the C-21-C-22 bond of the pyrene fragment as the energetically most favourable first step of the oxidative degradation . Localization energies calculated within the simple Huckel model pred ict that the attack of the C-21-C-22 pair by ozone is most probably al so kinetically the most preferred reaction path. The rather low locali zation energy of C-20 in the pyrene fragment indicates the possibility of competitive reactions between ozonolysis and the formation of phen ols and quinones. The theoretical results are supported by experimenta l findings on the ozonation of indeno[1,2,3-c,d]pyrene in aqueous medi um.