Charge localization in the carbonium ions of methylbenzanthracenes. [Deuterium exchange in carcinogenic and noncarcinogenic methylbenzanthracenes]

Journal Article · Sat Jul 31 20:00:00 EDT 1976 · J. Org. Chem.; (United States)

DOI:https://doi.org/10.1021/jo00878a003· OSTI ID:7335751

Cavalieri, E; Calvin, M

Covalent binding of aromatic hydrocarbons to cellular macromolecules, the first probable step in the tumor-initiating process, requires metabolic activation by monooxygenase enzyme systems. Acid-catalyzed proton--deuterium exchange was used as a model to simulate the electrophilic oxygen atom activated by such enzymes. Kinetics of exchange with deuterium ion for a series of carcinogenic and noncarcinogenic methylbenzanthracenes were studied by NMR in two sets of conditions, i.e., CCl/sub 4/--CF/sub 3/COOD (85:15 v/v and 50:50 v/v). Deuteration of the potent carcinogen 7,12-dimethylbenz(..cap alpha..)anthracene at the most basic position C-12 generated a carbonium ion with charge localized at the complementary 7 position, resulting in the specific deuteration of the attached methyl group. Similarly, selective attack of deuterium ion on C-6 in 3-methylcholanthrene produced a carbonium ion with a high degree of charge localization at C-12b and, consequently, specific deuteration at the adjacent methylene group. This study has revealed that charge localization in the carbonium ion renders this intermediate chemically reactive; such a distinctive property might play a role in the bioactivation of these compounds.

• Research Organization: Univ. of Nebraska, Omaha
• OSTI ID: 7335751
• Journal Information: J. Org. Chem.; (United States), Journal Name: J. Org. Chem.; (United States) Vol. 41:16; ISSN JOCEA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400303* -- Organic Chemistry-- Isotope Exchange & Isotope Separation-- (-1987)
ALKYL RADICALS
ANTHRACENE
AROMATICS
ARYL RADICALS
BENZYL RADICALS
CARCINOGENS
CONDENSED AROMATICS
DEUTERIUM
DISEASES
ENZYMES
HYDROCARBONS
HYDROGEN ISOTOPES
ISOTOPES
ISOTOPIC EXCHANGE
LIGHT NUCLEI
METHYL RADICALS
NEOPLASMS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
RADICALS
STABLE ISOTOPES