Improved syntheses of non-dioxin-like polychlorinated biphenyls (PCBs) and some of their sulfur-containing metabolites

Sanjay Telu; Sean Parkin; Larry W Robertson; Hans-Joachim Lehmler

doi:10.1016/j.envint.2009.01.013

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Improved syntheses of non-dioxin-like polychlorinated biphenyls (PCBs) and some of their sulfur-containing metabolites

Journal article

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Improved syntheses of non-dioxin-like polychlorinated biphenyls (PCBs) and some of their sulfur-containing metabolites

Sanjay Telu, Sean Parkin, Larry W Robertson and Hans-Joachim Lehmler

Environment international, Vol.36(8), pp.828-834

2010

DOI: 10.1016/j.envint.2009.01.013

PMCID: PMC2948577

PMID: 19261331

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https://doaj.org/article/e937e870c2d241759c5e7d8c35bb825fView

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Abstract

Polychlorinated biphenyls (PCBs) are an important group of environmental pollutants that have been associated with adverse human health effects. Despite recent advances in their synthesis, the availability of PCB congeners in sufficient quantity and purity still represents one obstacle in the investigation of their biological effects. We report herein improved syntheses of PCB congeners (and their metabolites) containing two or more ortho-chlorine substituents. The Suzuki coupling reaction at 110 °C yielded PCB congeners with a 2,2′-substitution pattern in good yields (78–99%), but failed to give PCB congeners with 3 or 4 ortho chlorine substituents. Symmetrically substituted PCB congeners with multiple ortho chlorine substituents were obtained in 20–52% yields using a modified Ullmann coupling reaction. The yield of the coupling increased with increasing degree of chlorination of the starting material. The modified Ullmann coupling reaction employed much milder reaction conditions (copper–bronze/CuCl in N-methylpyrrolidinone, 110 °C) and, therefore, appears to be advantageous compared to the classical Ullmann coupling reaction (copper–bronze, no solvent, 230 °C). PCBs 136 and 155 prepared via the modified Ullmann coupling reaction were nitrated and reduced with Na 2S 2O 4 to the corresponding amino-PCBs. Subsequently, the amino-PCBs were converted into sulfur-containing PCB metabolites or PCB 184 via the corresponding diazonium salt. These modified reaction conditions allow the synthesis of large quantities of pure, non-dioxin-like PCB congeners and their sulfur-containing metabolites for environmental and toxicological studies by overcoming problems associated with classical PCB synthesis strategies.

Suzuki coupling

Dihedral angle

Ullmann coupling

PCB 184

PCB 47

Methylsulfonyl PCB

Crystal structure

Details

Title: Subtitle: Improved syntheses of non-dioxin-like polychlorinated biphenyls (PCBs) and some of their sulfur-containing metabolites
Creators: Sanjay Telu - The University of Iowa, Department of Occupational and Environmental Health, 100 Oakdale Campus, 124 IREH, Iowa City, IA 52242, USA
Sean Parkin - University of Kentucky, Department of Chemistry, Lexington, KY 40506, USA
Larry W Robertson - The University of Iowa, Department of Occupational and Environmental Health, 100 Oakdale Campus, 124 IREH, Iowa City, IA 52242, USA
Hans-Joachim Lehmler - The University of Iowa, Department of Occupational and Environmental Health, 100 Oakdale Campus, 124 IREH, Iowa City, IA 52242, USA
Resource Type: Journal article
Publication Details: Environment international, Vol.36(8), pp.828-834
DOI: 10.1016/j.envint.2009.01.013
PMID: 19261331
PMCID: PMC2948577
NLM abbreviation: Environ Int
ISSN: 0160-4120
eISSN: 1873-6750
Publisher: Elsevier Ltd
Language: English
Date published: 2010
Academic Unit: Occupational and Environmental Health; Iowa Neuroscience Institute; Iowa Superfund Research Program
Record Identifier: 9984001077102771

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