Absolute configurations of K-region epoxide enantiomers of 3-methylcholanthrene, benz[a]anthracene, and benzo[a]pyrene

Weems, Henri B.; Mushtaq, Mohammad; Yang, Shen K.

doi:10.1021/ac00149a011

Cited by 6 publications

(4 citation statements)

References 32 publications

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“…Absolute configurations of 5,6-epoxide enantiomers have been elucidated by procedures (summarized in Figure 8) similar to those previously reported (12,15,18,33). Up to the present time, absolute configurations of K-region epoxide enantiomers of benz[a]anthracene, benzo[a]pyrene, l-methylbenz[a]anthracene, 4-methylbenz[a]anthracene, 7-methylbenz [a] anthracene, 11-methylbenz-[a]anthracene, 12-methylbenz[a]anthracene, 7,12-dimethylbenz[a]anthracene, benzo[c]phenanthrene, and chrysene have been established by the same approach (reference 35 and references cited therein).…”

Section: Discussionsupporting

confidence: 77%

“…In an earlier report (27), we indicated that enantiomers of DBA 5,6-epoxide are resolved on an ionically bonded R-DNBPG column, but not on the covalently bonded R-DNBPG column (see also Table I). The elution order of enantiomeric DBA 5,6-epoxides on ionically bonded R-DNBPG is the same as those of other enantiomeric K-region epoxides (18). Recently, Platt and Reischmann (4) stated that they could not confirm our earlier results by using the same CSP column.…”

Section: Discussioncontrasting

confidence: 50%

“…Taken together, the results established that the 5,6-epoxide enantiomer, more strongly retained on the ionically bonded fi-DNBPG column, has a 5S,6R absolute stereochemistry. The approach in elucidating the absolute configurations of enantiomeric DBA 5.6epoxides is summarized in Figure 8 and is similar to those described earlier (18). Enantiomeric Purity of Biosynthetic DBA 5,6-Epoxides.…”

Section: Resultsmentioning

confidence: 94%

“…Enantiomeric purity of metabolically formed K-region epoxides and irans-dihydrodiols may be determined directly on CSP-HPLC and/or by CD spectral analyses. Absolute configurations of epoxide enantiomers may be determined by their glutathione conjugates (17) and by stereochemical analyses of their methoxylation products (12,15,18,19).…”

Section: Introductionmentioning

confidence: 99%

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Stereoselective formations of enantiomeric K-region epoxide and trans-dihydrodiols in dibenz[a,h]anthracene metabolism

Mushtaq¹,

Weems²,

Yang³

1989

Chem. Res. Toxicol.

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Metabolism of dibenz[a,h]anthracene (DBA) to optically active epoxide and dihydrodiol products by rat liver microsomes was investigated. Enantiomeric separation of K-region 5,6-epoxide, trans- and cis-5,6-dihydrodiols, non-K-region trans-1,2- and trans-3, 4-dihydrodiols, and O-methyl ethers derived from methoxylation of racemic and enantiomeric K-region 5,6-epoxides was performed on HPLC columns packed with Pirkle chiral stationary-phase (CSP) (R)-N-(3,5-dinitrobenzoyl)phenylglycine (R-DNBPG) or (S)-N-(3,5-dinitrobenzoyl) leucine (S-DNBL), which was either ionically or covalently bonded to a silica gel support. Enantiomers of DBA 5,6-epoxide, trans-5,6-dihydrodiol, and its two isomeric O-methyl ethers were efficiently separated on the ionically bonded R-DNBPG column. Enantiomers of DBA cis-5, 6-dihydrodiol were resolved on both ionically and covalently bonded S-DNBL columns. Enantiomeric pairs of the non-K-region trans-1,2- and 3,4-dihydrodiols were poorly resolved on all CSPs tested. DBA was incubated with a NADPH-regenerating system and liver microsomes from untreated, phenobarbital- (PB) treated, 3-methylcholanthrene- (MC) treated, and polychlorinated biphenyl (PCB, Aroclor 1254) treated rats either in the absence or in the presence of an epoxide hydrolase inhibitor, 3,3,3-trichloropropylene 1,2-oxide (TCPO). Metabolites formed were analyzed by reversed-phase, normal-phase, and CSP HPLC. CD spectral and CSP-HPLC analyses of metabolically formed trans-dihydrodiols indicated that the dihydrodiols are highly enriched in the R,R-enantiomers.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionsupporting

confidence: 77%

Section: Discussioncontrasting

confidence: 50%

Section: Resultsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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Stereoselective formations of enantiomeric K-region epoxide and trans-dihydrodiols in dibenz[a,h]anthracene metabolism

Mushtaq¹,

Weems²,

Yang³

1989

Chem. Res. Toxicol.

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Resolution of four k‐region arene imines and mutagenicity of the optically pure aziridines

Blum

Cohen

Levin

et al. 1998

Journal of Heterocyclic Chem

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Racemic K‐region imines of benz[a]anthracene, 7‐methylbenz[a]anthracene, chrysene and benzo[a]pyrene (1–4, respectively) have been resolved by high performance liquid chromatography on a column packed with amylose tris(3,5‐dimethylphenylcarbamate) on silica gel. The absolute configuration of the resolved aziridines was assigned by comparison of their circular dichromism spectra to those of the corresponding enantiomerically pure arene oxides. The mutagenicity of the enantiomers of the arene imines was investigated using Salmonella typhimurium strains TA98 and TA100. Although all arene imines investigated were potent mutagens, quantitative and qualitative differences in the mutagenic activity were observed between enantiomers.

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Stereoselectivity of cytochrome P-450 isozymes and epoxide hydrolase in the metabolism of polycyclic aromatic hydrocarbons

Yang

1988

Biochemical Pharmacology

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Absolute configurations of K-region epoxide enantiomers of 3-methylcholanthrene, benz[a]anthracene, and benzo[a]pyrene

Cited by 6 publications

References 32 publications

Stereoselective formations of enantiomeric K-region epoxide and trans-dihydrodiols in dibenz[a,h]anthracene metabolism

Stereoselective formations of enantiomeric K-region epoxide and trans-dihydrodiols in dibenz[a,h]anthracene metabolism

Resolution of four k‐region arene imines and mutagenicity of the optically pure aziridines

Stereoselectivity of cytochrome P-450 isozymes and epoxide hydrolase in the metabolism of polycyclic aromatic hydrocarbons

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