Synthesis of 13C-enriched benzo(a)pyrene derivatives, specifically those with C-13 label at the 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 position and related derivatives such as arene oxides having the label at the oxide carbon atoms. Selectivity studies of the reactions of carcinogenic electrophiles with biomolecules. Application of C-13 NMR to studies of the products of reactions of carcinogens with biomolecules. Evaluation of the sensitivity of C-13 NMR for metabolism studies. Synthesis of substrates for the generation of benzo(a)pyrenylmethyl cations in the bay region and certain non-bay regions, and the determination of kinetics of such cations with biomolecules. Studies of the photooxidation of benzo(a)pyrene. BIBLIOGRAPHIC REFERENCES: R. E. Royer, G. H. Daub, and D. L. Vander Jagt, J. Labelled Compounds and Pharmaceuticals, 12, 377-380 (1976), "Synthesis of Carbon-13 Labelled 6-Substituted Benzo(a)pyrenes". These syntheses were completed before CA16871 began; however, the materials prepared in this work are being used in CA16871.