Synthesis and structure determination of the adducts formed by electrochemical oxidation of the potent carcinogen dibenz[a,I]pyrene in the presence of nucleosides
- Univ. of Nebraska Medical Center, Omaha, NE (United States)
- Univ. of Nebraska, Lincoln, NE (United States)
Because dibenzo[a,I]pyrene (DBP) is the most potent known carcinogenic aromatic hydrocarbon, reference adducts formed by reaction of deoxyribonucleosides with electrophilic intermediates of DBP are essential for identifying the structures of adducts formed in biological systems. Electrochemical oxidation of DBP in the presence of nucleosides leads to adducts from DBP[sup +]. When 6.8 equiv of charge are consumed, three adducts are formed with dG: 7-(DBP-10-yl)Gua (89%), 8-(DBP-10-yl)dG (2%), and 8-(DBP-10-yl)Gua (2%). With 10 equiv of charge, however, only two adducts are formed: 7-(DBP-10-yl)Gua (89%) and 8-(DBP-10-yl)Gua (4%). Anodic oxidation of 8-(DBP-10-yl)dG yields 8-(DBP-10-yl)Gua. Anodic oxidation of DBP in the presence of G produces 7-(DBP-10-yl)Gua (27%) and 8-(DBP-10-yl)G (9%). Anodic oxidation of DBP in the presence of dA affords two adducts, N[sup 6]-(DBP-10-yl)dA (28%) and 7-(DBP-10-yl)Ade (12%), whereas anodic oxidation in the presence of A produces only N[sup 6]-(DBP-10-yl)A (24%). The structures of the adducts were elucidated by using UV, NMR, and MS. Formation of these adducts demonstrates that DBP[sup +] reacts at C-10 with nucleophiles. The most reactive nucleophilic groups for the Gua moiety are the N-7 and C-8, whereas for the Ade moiety they are N-7 and the 6-amino group. 21 refs., 5 figs., 1 tab.
- OSTI ID:
- 6820000
- Journal Information:
- Chemical Research in Toxicology; (United States), Journal Name: Chemical Research in Toxicology; (United States) Vol. 6:4; ISSN 0893-228X; ISSN CRTOEC
- Country of Publication:
- United States
- Language:
- English
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560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADDUCTS
AROMATICS
BENZOPYRENE
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
CARCINOGENESIS
CHEMICAL REACTIONS
CHEMISTRY
CONDENSED AROMATICS
DNA ADDUCTS
ELECTROCHEMISTRY
HYDROCARBONS
KINETICS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
OXIDATION
PATHOGENESIS
REACTION INTERMEDIATES
REACTION KINETICS
RIBOSIDES
SYNTHESIS