MOLECULAR-STRUCTURE OF BENZO(A)PYRENE 4,5-OXIDE

Google Scholar
  • 1 January 1976
    • journal article
    • research article
    • Vol. 36  (11) , 3951-3957
Abstract
An X-ray crystallographic study of benzo(a)pyrene 4,5-oxide, a metabolite of the carcinogen benzo(a)pyrene (BP), has given information on the geometry of this molecule. The C skeleton of BP itself was shown by others to be nearly planar; the planarity of the C skeleton was perturbed very little by epoxidation of the 4,5-double bond. Epoxidation did increase the double bond character of C-11-C-12, C-9-C-10 and C-7-C-8. The H atom on C-3 pointed directly toward the O atom of another molecule. This C.sbd.H...O interaction, although weak, suggested that C-3 might be slightly acidic. An analysis of the experimentally determined bond lengths indicated that, after the highly reactive epoxide ring, the most reactive positions were at C-1. C-6, C-7, C-11 and C-12. The oxide ring of BP, unlike that for the K-region oxide of 7,12-dimethylbenz(a)anthracene, was symmetrical (with C.sbd.O distances equivalent within experimental error). The C.sbd.O distances were longer than those found in most oxides, including those in 7,12-dimethyl-benz(a)anthracene-5,6-oxide. The oxide rings of the K-region oxides of the 2 potent carcinogens BP and 7,12-dimethylbenz(a)anthracene were not similar in dimensions.