111137-80-5Relevant articles and documents
Synthesis of 13C4-labelled oxidized metabolites of the carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene
Wu, Anhui,Xu, Daiwang,Lu, Ding,Penning, Trevor M.,Blair, Ian A.,Harvey, Ronald G.
, p. 7217 - 7233 (2012/09/05)
Polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (BaP), are ubiquitous environmental contaminants that are implicated in causing lung cancer. BaP is a component of tobacco smoke that is transformed enzymatically to active forms that interact with DNA. We reported previously development of a sensitive stable isotope dilution LC/MS method for analysis of BaP metabolites. We now report efficient syntheses of 13C4-BaP and the complete set of its 13C4-labelled oxidized metabolites needed as internal standards They include the metabolites not involved in carcinogenesis (Group A) and the metabolites implicated in initiation of cancer (Group B). The synthetic approach is novel, entailing use of Pd-catalyzed Suzuki, Sonogashira, and Hartwig cross-coupling reactions combined with PtCl2-catalyzed cyclization of acetylenic compounds. This synthetic method requires fewer steps, employs milder conditions, and product isolation is simpler than conventional methods of PAH synthesis. The syntheses of 13C4-BaP and 13C4-BaP-8-ol each require only four steps, and the 13C-atoms are all introduced in a single step. 13C4-BaP-8-ol serves as the synthetic precursor of all the oxidized metabolites of 13C-BaP implicated in initiation of cancer. The isotopic purities of the synthetic 13C 4-BaP metabolites were estimated to be ≥99.9%.
Analysis of phenanthrene and benzo[ a ]pyrene tetraol enantiomers in human urine: Relevance to the bay region diol epoxide hypothesis of benzo[ a ]pyrene carcinogenesis and to biomarker studies
Hecht, Stephen S.,Carmella, Steven G.,Villalta, Peter W.,Hochalter, J. Bradley
body text, p. 900 - 908 (2011/03/17)
One widely accepted metabolic activation pathway of the prototypic carcinogenic polycyclic aromatic hydrocarbon (PAH) benzo[a]pyrene (BaP) proceeds through the "bay region diol epoxide" BaP-(7R,8S)-diol-(9S,10R)- epoxide (2). However, few studies have addressed the analysis of human urinary metabolites of BaP, which result from this pathway. Phenanthrene (Phe) is structurally related to BaP, but human exposure to Phe is far greater, and its metabolites can be readily detected in urine. Thus, Phe metabolites have been proposed as biomarkers of PAH exposure and metabolic activation. Phe-tetraols in particular could be biomarkers of the diol epoxide pathway. While BaP-tetraols and Phe-tetraols have been previously quantified in human urine, no published studies have determined their enantiomeric composition. This is important because different enantiomers would result from the bay region diol epoxide and "reverse" diol epoxide pathways, the latter being associated with weak mutagenicity and carcinogenicity. We addressed this problem using chiral HPLC to separate the enantiomers of BaP-7,8,9,10-tetraol and Phe-1,2,3,4-tetraol. Urine samples from smokers were subjected to solid-phase extraction, chiral HPLC, and GC-NICI-MS/MS analysis for silylated Phe-1,2,3,4-tetraols. The results demonstrated that >96% of Phe-1,2,3,4-tetraol in smokers urine was Phe-(1S,2R,3S,4R)-tetraol (12), resulting from the "reverse" diol epoxide pathway, whereas less than 4% resulted from the "bay region diol epoxide" pathway of Phe metabolism. Urine from creosote workers was similarly analyzed for BaP-7,8,9,10-tetraol enantiomers. In contrast to the results of the Phe-tetraol analyses, 78% of BaP-7,8,9,10-tetraol in these human urine samples was BaP-(7R,8S,9R,10S)-tetraol (3) resulting from the "bay region diol epoxide" pathway of BaP metabolism. These results provide further support for the bay region diol epoxide pathway of BaP metabolism in humans and demonstrate differences in BaP and Phe metabolism, which may be important when considering Phe-tetraols as biomarkers of PAH metabolic activation.
Enantioselective Synthesis of the (+)-anti-7,8-Dihydrodiol-9,10-epoxide of the Potent Carcinogen Benzopyrene
Huang, Xiaoming,Harris, Thomas M.
, p. 1699 - 1700 (2007/10/02)
The title compound, the most important genotoxic metabolite of benzopyrene, has been prepared efficiently in a synthesis which capitalized on Jacobsen-type enantioselective epoxidation of 9,10-dihydrodibenzopyrene, cleavage of the epoxide by KOH-Me2SO to give the tetrahydro-trans-7,8-diol, and formation of the dibenzoate from which the contaminating antipode was removed by crystallization.
Improved Formal Preparation of Enantiomerically Pure anti-Benzopyrene Diol Epoxide.
Negrete, George R.,Meehan, Thomas
, p. 4727 - 4730 (2007/10/02)
We report an improved, economical formal route to enantiomerically pure anti-benzopyrene diol epoxide (BPDE).A trimethylaluminum catalyzed regio- and stereoselective opening of racemic 7,8-epoxy-7,8,9,10-tetrahydrobenzopyrene with Mosher's acid delivers benzylic esters exclusively.This step is a significant improvement over the lack of regioselectivity of standard procedures.We also show that modification of the subsequent chemical steps further shortens the preparation of enantiomerically pure anti-BPDE.
