Chlorination increases the persistence of semiquinone free radicals derived from polychlorinated biphenyl hydroquinones and quinones

Yang Song; Garry R Buettner; Sean Parkin; Brett A Wagner; Larry W Robertson; Hans-Joachim Lehmler

doi:10.1021/jo801397g

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Chlorination increases the persistence of semiquinone free radicals derived from polychlorinated biphenyl hydroquinones and quinones

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Chlorination increases the persistence of semiquinone free radicals derived from polychlorinated biphenyl hydroquinones and quinones

Yang Song, Garry R Buettner, Sean Parkin, Brett A Wagner, Larry W Robertson and Hans-Joachim Lehmler

Journal of organic chemistry, Vol.73(21), pp.8296-8304

11/07/2008

DOI: 10.1021/jo801397g

PMCID: PMC2629131

PMID: 18839991

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Abstract

Polychlorinated biphenyls (PCBs) comprise a group of persistent organic pollutants that differ significantly in their physicochemical properties, their persistence, and their biological activities. They can be metabolized via hydroxylated and dihydroxylated metabolites to PCB quinone intermediates. We have recently demonstrated that both dihydroxy PCBs and PCB quinones can form semiquinone radicals (SQ(*-)) in vitro. These semiquinone radicals are reactive intermediates that have been implicated in the toxicity of lower chlorinated PCB congeners. Here we describe the synthesis of selected PCB metabolites with differing degrees of chlorination on the oxygenated phenyl ring, e.g., 4,4'-dichloro-biphenyl-2,5-diol, 3,6,4'-trichloro-biphenyl-2,5-diol, 3,4,6,-trichloro-biphenyl-2,5-diol, and their corresponding quinones. In addition, two chlorinated o-hydroquinones were prepared, 6-chloro-biphenyl-3,4-diol and 6,4'-dichloro-biphenyl-3,4-diol. These PCB (hydro-)quinones readily react with oxygen or via comproportionation to yield the corresponding semiquinone free radicals, as detected by electron paramagnetic resonance spectroscopy (EPR alias ESR). The greater the number of chlorines on the (hydro-)quinone (oxygenated) ring, the higher the steady-state level of the resulting semiquinone radical at near neutral pH.

Polychlorinated Biphenyls - chemistry

Quinones - chemistry

Electron Spin Resonance Spectroscopy

Hydroquinones - chemistry

Halogenation

Oxygen - chemistry

Benzoquinones - chemical synthesis

Environmental Pollutants - metabolism

Polychlorinated Biphenyls - metabolism

Details

Title: Subtitle: Chlorination increases the persistence of semiquinone free radicals derived from polychlorinated biphenyl hydroquinones and quinones
Creators: Yang Song - Department of Occupational and Environmental Health, The University of Iowa, 100 Oakdale Campus, 124 IREH, Iowa City, Iowa 52242-5000, USA
Garry R Buettner
Sean Parkin
Brett A Wagner
Larry W Robertson
Hans-Joachim Lehmler
Resource Type: Journal article
Publication Details: Journal of organic chemistry, Vol.73(21), pp.8296-8304
DOI: 10.1021/jo801397g
PMID: 18839991
PMCID: PMC2629131
NLM abbreviation: J Org Chem
ISSN: 0022-3263
eISSN: 1520-6904
Publisher: American Chemical Society (ACS); United States
Grant note: P30 ES005605 / NIEHS NIH HHS R01 GM073929 / NIGMS NIH HHS P30 ES005605-17 / NIEHS NIH HHS P42 ES013661 / NIEHS NIH HHS P42 ES013661-01A1 / NIEHS NIH HHS R01GM073929 / NIGMS NIH HHS P42 ES013661-02 / NIEHS NIH HHS ES012475 / NIEHS NIH HHS K25 ES012475-03 / NIEHS NIH HHS R01 GM073929-01A2 / NIGMS NIH HHS K25 ES012475 / NIEHS NIH HHS ES013661 / NIEHS NIH HHS P30 ES005605-16 / NIEHS NIH HHS P42 ES013661-03 / NIEHS NIH HHS K25 ES012475-04 / NIEHS NIH HHS K25 ES012475-05 / NIEHS NIH HHS P30 ES005605-18 / NIEHS NIH HHS ES05605 / NIEHS NIH HHS
Language: English
Date published: 11/07/2008
Academic Unit: Occupational and Environmental Health; Iowa Neuroscience Institute; Radiation Oncology; Iowa Superfund Research Program
Record Identifier: 9984000922302771

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