Efficient reduction of polycyclic quinones, hydroquinones, and phenols with hydriodic acid

Konieczny, M.; Harvey, Ronald G.

doi:10.1021/jo00394a014

Cited by 60 publications

(24 citation statements)

References 2 publications

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“…Results reported here indicate that after ingesting a high PAH meal, 1-OHPY is eliminated with a mean t,, of 4-4 (SD 1-1) h and that there is a lag time to the occurrence of the maximal elimination rate of 6-3 (SD [1][2][3][4][5] h. These parameters of elimination suggest that a sampling strategy that relates an exposure at time t = 0 to urine sampling from time t = 0 to 24 h will capture most of the elimination attributable to that exposure.…”

Section: Discussionmentioning

confidence: 96%

An examination of the time course from human dietary exposure to polycyclic aromatic hydrocarbons to urinary elimination of 1-hydroxypyrene.

Buckley

Lioy²

1992

Occupational and Environmental Medicine

114

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The significance of diet as an exposure route for polycyclic aromatic hydrocarbons (PAHs) and the associated kinetics of urinary 1-hydroxypyrene (1-OHPY) elimination were examined through a controlled human exposure study. Results showed that a 100 to 250-fold increase in a dietary benzo(a)pyrene (BaP) PAHs is potentially substantial and therefore it is likely to be a confounding cofactor in its effect on urinary 1-OHPY concentrations when trying to isolate the effect of other exposure routes. The present study examines (1) the effect of dietary exposure on the urinary 1-OHPY elimination rate and (2) the time course of 1-OHPY elimination after the ingestion of a meal high in PAHs.Biomarkers provide advantages in eliminating the uncertainties associated with host characteristics (for example, sex, age, diet, and activity) and the characteristics of the contaminant (for example, substrate, solubility, stability, and particle size). A biomarker, however, cannot differentiate the routes of exposure without knowledge of the concentration of the contaminant in the media and the subjects' contact with the media.A biomarker of exposure is established by defining a predictive relation between external measures of exposure and biological concentrations. Because exposure and the appearance of the biomarker in urine does not occur simultaneously, relating these variables requires characterisation of their time course from contact through elimination.Although investigation of PAH biomarkers (total or carcinogenic) is generally of interest, the analytical requirements for assaying many such compounds at trace concentrations are impractical. Attempts to develop biological markers for PAH exposure comprise several different approaches.Firstly, reverse metabolism, which involves the chemical reduction of the dozens of urinary metabolites back to the parent PAH.

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Section: Discussionmentioning

confidence: 96%

An examination of the time course from human dietary exposure to polycyclic aromatic hydrocarbons to urinary elimination of 1-hydroxypyrene.

Buckley

Lioy²

1992

Occupational and Environmental Medicine

114

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“…The starting material (Sigma, custom synthesis, 6.1 mCi-mmol-1; 1 Ci = 37 GBq) was diluted with unlabeled AQ to 3.0 mCi mmol-' and repurified by preparative TLC on silica gel 60 (Merck) in CH2C12/tetrahydrofuran (99:1) to a radiochemical purity of 98.3%. A portion of this sample (20 mg) was reduced with hydriodic acid (11), and the resulting crude [1-4, (14). Procedures for the purification of LiP, the in vitro oxidation of AC with LiP, and the analysis of oxidation products by TLC and GC/MS were as described previously (10,14).…”

Section: Methodsmentioning

confidence: 99%

Ring fission of anthracene by a eukaryote.

Hammel

Green

Gai

1991

Proc. Natl. Acad. Sci. U.S.A.

116

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Ligninolytic fungi are unique among eukaryotes in their ability to degrade polycyclic aromatic hydrocarbons (PAHs), but the mechanism for this process is unknown. Although certain PAHs are oxidized in vitro by the fungal lignin peroxidases (LiPs) that catalyze lig olysis, it has never been shown that LiPs initiate PAH degradation in vivo. To address these problems, the metabolism of anthracene (AC) and its in vitro oxidation product, 9,10-anthraquinone (AQ), was examined by chromatographic and isotope dilution techniques in Phanerochaete chrysosporium. The fungal oxidation of AC to AQ was rapid, and both AC and AQ were significantly mineralized. Both compounds were cleaved by the fungus to give the same ring-flssion metabolite, phthalic acid, and phthalate production from AQ was shown to occur only under ligninolytic culture conditions. These results show that the major pathway for AC degradation in Phanerochaete proceeds AC -+ AQ --phthalate + CO2 and that it is probably mediated by LiPs and other enzymes of ligninolytic metabolism.Polycyclic aromatic hydrocarbons (PAHs) are major pollutants of both anthropogenic and natural pyrolytic origin, occurring in soils, sediments, and airborne particulates. The crucial step in their biodegradation is oxidative fission of the fused aromatic ring system, an event previously thought unique to certain bacteria (1). Recent evidence necessitates a revision of this view: the lignin-degrading fungi that cause white-rot of wood have also been shown to mineralize a wide variety of aromatic pollutants, including certain PAHs, under culture conditions that promote the expression of ligninolytic metabolism (2-5). A key component of the fungal ligninolytic system is thought to consist of extracellular lignin peroxidases (LiPs), which catalyze the one-electron oxidation of various lignin-related substrates (6-8). LiPs have also been shown to oxidize certain PAHs in vitro, and it has been proposed that they play an important role in the degradation of these pollutants by white-rot fungi (9, 10). However, it has never been demonstrated that LiP-catalyzed oxidation is a significant fate ofany PAH in vivo or that the products of such a reaction are subsequently cleaved to smaller, monocyclic, compounds. In fact, to our knowledge, no PAH ring-fission metabolite other than CO2 has ever been identified in any eukaryote. To address these problems, we have examined the fate of anthracene (AC) in cultures of the ligninolytic basidiomycete Phanerochaete chrysosporium, and we now report that ligninolytic metabolism provides a route for the ring fission of this PAH. AC trans-1,2-dihydrodiol was synthesized from 1,2-dihydroxy-AQ (alizarin) as previously described (12, 13) [ring-'4C]Phthalic acid (12.7 mCi-mmol-1, radiochemical purity >98%) was from Sigma. Unlabeled phthalic acid (99%) and AQ (>98%) were from Kodak. All other reagents were of the highest commercially available quality. MATERIALS AND METHODSTo minimize the artifactual oxidation of AC or its metabolites, all syntheses, cultu...

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“…A possible reduction mechanism is proposed in Supplementary Figure S2 6,11 . The most informative analysis to support the reduction of G-O was elemental analysis (EA) of the raw graphite, G-O and RG-O (Supplementary Table S1).…”

Section: Rg-o Powdersmentioning

confidence: 99%

“…Hydriodic acid with acetic acid (HI-AcOH) has been reported to efficiently convert polycyclic quinones and phenols into their corresponding arenes in excellent yield 11 . It was suggested that this organic reducing agent with iodide as a catalyst would replace the oxygen functional groups (epoxides and alcohols) with organohalides, which are good leaving groups, and produce high-quality RG-O in both solution and gas phases.…”

mentioning

confidence: 99%

Reduced graphene oxide by chemical graphitization

et al. 2010

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Reduced graphene oxides (RG-os) have attracted considerable interest, given their potential applications in electronic and optoelectronic devices and circuits. However, very little is known regarding the chemically induced reduction method of graphene oxide (G-o) in both solution and gas phases, with the exception of the hydrazine-reducing agent, even though it is essential to use the vapour phase for the patterning of hydrophilic G-os on prepatterned substrates and in situ reduction to hydrophobic RG-os. In this paper, we report a novel reducing agent system (hydriodic acid with acetic acid (HI-AcoH)) that allows for an efficient, one-pot reduction of a solution-phased RG-o powder and vapour-phased RG-o (VRG-o) paper and thin film. The reducing agent system provided highly qualified RG-os by mass production, resulting in highly conducting RG-o HI − AcoH . moreover, VRG-o HI − AcoH paper and thin films were prepared at low temperatures (40 °C) and were found to be applicable to flexible devices. This one-pot method is expected to advance research on highly conducting graphene platelets.

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Efficient reduction of polycyclic quinones, hydroquinones, and phenols with hydriodic acid

Cited by 60 publications

References 2 publications

An examination of the time course from human dietary exposure to polycyclic aromatic hydrocarbons to urinary elimination of 1-hydroxypyrene.

An examination of the time course from human dietary exposure to polycyclic aromatic hydrocarbons to urinary elimination of 1-hydroxypyrene.

Ring fission of anthracene by a eukaryote.

Reduced graphene oxide by chemical graphitization

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