Synthesis,in Vitro Metabolism,Mutagenicity, and DNA-Adduction of Naphtho[1,2- e ]pyrene

Literature data, although limited, underscore the contribution of C 24 H 14 polycyclic aromatic hydrocarbons to the biological activity of the extracts of complex environmental samples. However, little attention has been given to naphthopyrene (NP) isomers due to lack of synthetic standards and, therefore, lack of studies aimed at unequivocal identification of C 24 H 14 isomers in environmental samples. We hypothesize that naphtho[1,2- e ]pyrene (N[1,2- e ]P), having a fjord region and a bay region might be a potent mutagen. To test our hypothesis, we synthesized N[1,2- e ]P by Suzuki reaction and examined its in vitro metabolism with the S 9 fraction from phenobarbital/ g -naphthoflavone-induced rat liver homogenates. We have tentatively identified its K-region diol as the major metabolite and a fjord region dihydrodiol as minor metabolite. Contrary to our hypothesis, N[1,2- e ]P was not mutagenic in S. typhimurium strain TA 100 and did not induce morphological cell transformation in mammalian cells. Its metabolite, 11,12-dihydroxy-11,12-dihydro-N[1,2- e ]P was a weak mutagen. The reaction of calf thymus DNA with N[1,2- e ]P-11,12-diol-13,14-epoxide showed that it reacts predominately with the exocyclic amino group of adenine.     

An Abbreviated Synthesis of 7,12-Dimethylbenz[ a ]anthracene and Benzo[ c ]chrysene Metabolites Using the Suzuki Reaction

Efficient syntheses of important metabolites of 7,12-dimethylbenz[ a ]anthracene (DMBA) and benzo[ c ]chrysene (B[ c ]C), via Suzuki coupling reaction are described. This approach provides an excellent method for the preparation of 3-methoxy-DMBA 5 , 10-methoxy-B[ c ]C 14 and 2-methoxy B[ c ]C 20 , and hence for the corresponding dihydrodiols 6 , 15 , and 21 . Following a similar Suzuki reaction, DMBA-6(5 H )-one 8 was also synthesized in high yield.     

Syntheses of Dibenzo[h,rst]Pentaphene and Naphtho[1,2,3,4-rst]Pentaphen

Abstract

Syntheses of the fused heptacyclic polyarenes dibenzo[h,rst]pentaphene (1), naphthol[1,2,3,4-rst]pentaphene (2), and the pentacyclic polyarene 8H-naphth[1,2,3-de]anthracene (8), of interest in carcinogenesis research, are described.     

Syntheses and Identification of Benzo[C]Chrysene Metabolites

Like other PAHs, chrysenes are thought to exert their carcinogenicity via metabolic activation of proximally carcinogenic dihydrodiols to diol epoxides as ultimate carcinogens. Benzo[c] chrysene (B[c]C) is structurally intriguing among the PAH because it features both a bay region and a fjord region. Although B[c]C is carcinogenic and mutagenic, few data are available on its metabolic activation or the nature of its metabolites.

We have synthesized the B[c]C trans-1,2-, 7,8-, and 9,10-dihydrodiols from the appropriate methoxy-substituted bisnaphthyl olefins by photochemical cyclization. B[c]C was metabolized with S9 liver fraction from phenobarbital/β-naphthoflavone-treated rats. Dihydrodiols were formed on both terminal rings as well as in the K-region. 2-, 3-, and 10-HydroxyB[c]C were also identified as metabolites. In mutagenicity studies toward S. typhimurium TA100, 1,2-dihydrodiol was more mutagenic than B[c]C at doses above 1.25 μg/plate, whereas 9,10-dihydrodiol was toxic at doses above 1.25 μg/plate.     

A Coupled-Column HPLC Method for Routine Analysis of Various Chrysene and Benzo[a]Pyrene Metabolites in Urine

The carcinogenic potential of some PAHs leads to the necessity of expressive biological monitoring for people occupationally exposed to PAH. A highly automated, coupled-column, high performance liquid chromatography method for the simultaneous quantification of several chrysene and benzo[a]pyrene metabolites in urine of exposed subjects is presented. After enzymatic hydrolysis of the metabolites, the sample can be directly injected into the HPLC system. The instrumental set-up comprises an analytical column and a precolumn, connected via a 6-port switching valve. Clean-up and analyte preconcentration are automatically performed on the precolumn which is packed with copper-phthalocyanine modified silica. Afterwards, analytes are automatically transferred onto the analytical column where separation is carried out by elution with a methanol-water gradient. Detection of the analytes makes use of their natural fluorescence. Thus, clean-up and analytical separation require little time, making the method suitable for routine analysis in biomonitoring.     

咪唑并[1,2-b]哒嗪的合成研究

咪唑并[1，2-b]哒嗪是第四代头孢菌素——头孢唑兰的重要中间体。以3，6-二氯哒嗪为原料，经氨解得到3-氨基-6-氯哒嗪，与溴乙醛成环形成6-氯咪唑并[1，2-b]哒嗪，再在催化剂作用下氢解成咪唑并[1，2-b]哒嗪。考察了反应温度、时间、物料配比、压力、催化剂用量等反应条件对收率的影响。总收率达到41％。用熔点，核磁共振谱和元素分析对产品结构进行表征。     

UVA Light-Induced DNA Single-Strand Cleavage by Hydroxybenzo[ a ]pyrenes

UVA light-induced DNA single-strand cleavage by 1-hydroxy, 3-hydroxy, 7-hydroxy, and 9-hydroxybenzo[ a ]pyrenes (OH-B a Ps) and 6-acetoxybenzo[ a ]pyrene (6-OAc-B a P) was studied. Under experimental conditions, the concentrations of 1-OH, 3-OH, 7-OH, and 9-OH-B a Ps and 6-OAc-B a P needed to cause 25% of the supercoiled form I plasmid DNA to become relaxed form II DNA were found to be 0.6, 2.5, 1.0, 1.3, and 1.1 w M, respectively. These concentrations are all smaller than that of B a P, which was 6 w M. These results indicate that on photoirradiation, OH-B a Ps are more cytotoxic and/or genotoxic than their parent compound, B a P. Mechanistic studies reveal that singlet oxygen and superoxide free radicals are involved in causing DNA cleavage.     

Synthesis and Structure Determination of the Adducts of Dibenzo[a,l]pyrene Diol Epoxides and Deoxyadenosine or Deoxyguanosine

Abstract

(±)?Syn?dibenzo[a,l]pyrene diol epoxide (DB[a,l]PDE) and (±)?anti?DB[a,l]PDE were reacted with deoxyadenosine (dA) or deoxyguanosine (dG) in dimethylformamide at 100 °C for 30 min. The crude products were purified by reverse phase HPLC under gradient and isocratic conditions. The structure of each adduct was assigned by 1D and 2D NMR spectra and by fast atom bombardment mass spectrometry. Five adducts were isolated from the reaction of (±)?syn?DB[a,l]PDE and dA: syn?DB[a,l]PDE?N⁶dA?1, syn?DB[a,l]PDE?N⁶dA?2, syn?DB[a,l]PDE?N⁶dA?3, syn?DB[a,l]PDE?N⁶dA?4 and syn?DB[a,l]PDE?N7Ade. Four adducts were isolated from the reaction of (±)?anti?DB[a,l]PDE and dA: anti?DB[a,l]PDE?N⁶dA?1, anti?DB[a,l]PDE?N⁶dA?2, anti?DB[a,l]PDE?N⁶dA?3 and anti?DB[a,l]PDE?N⁶dA?4. Two adducts were isolated from the reaction of (±)?syn?DB[a,l]PDE and dG: (±)?11,12,13?trihydroxy?tetrahydroDB[a,l]P?14?N²dG and (±)?11,12,13?trihydroxy?tetrahydroDB[a,l]P?14?N7Gua. Two adducts were isolated from the reaction of (±)?anti?DB[a,l]PDE and dG: (±)?11,12,13?trihydroxy?tetrahydroDB[a,l]P?14?N²dG and (±)?11,12,13?trihydroxy?tetrahydroDB[a,l]P?14?N7Gua.     

Synthesis of 2-Hydroxybenzo[a]pyrene,a Tumorigenic Phenol Derivative of Benzo[a]pyrene

An efficient synthesis of 2-hydroxybenzo[a]pyrene (1a) from 4,5,9,10-tetrahydropyrene via 2-methoxy-4,5,9,10-tetrahydropyrene (2e) is described. Friedel–Crafts acetylation of tetrahydropyrene affords the 2-acetyl derivative which is transformed to the 2-methoxy derivative 2e via Baeyer–Villager oxidation, hydrolysis, and treatment with dimethyl sulfate. Friedel–Crafts succinoylation of 2e with succinic anhydride and AlCl₃ takes place regiospecifically in the 7-position. The product is transformed to 1a via Clemmensen reduction, HF cyclization, Wolff–Kishner reduction, catalytic dehydrogenation, and demethylation with HBr.     

DETERMINATION OF DIBENZO[A,L]PYRENE AND OTHER FJORD-REGION PAH ISOMERS WITH MW 302 IN ENVIRONMENTAL SAMPLES

Polycyclic aromatic hydrocarbons (PAHs) occur in the environment as complex mixtures including compounds with mutagenic and carcinogenic activity. The PAH profile routinely determined in environmental samples at present encompasses isomers with molecular weight (MW) not greater than 300. However, PAHs with MW >300 have been demonstrated for several matrices to contribute up to 50% of the total activity when tested for carcinogenicity in experimental animals. Recent studies indicate that among the dibenzopyrenes with MW 302 dibenzo[a,l]pyrene, possessing a fjord region, is by far the most carcinogenic PAH hitherto identified. To further elucidate the environmental relevance of this compound we have applied the isotope dilution GC/MS technique as analytical procedure to determine this compound and the related fjord region PAH naphtho[1,2-a]- and naphtho[1,2-e]pyrene in various matrices. Identification was based on comparison of UV and mass spectra as well as retention times of authentic reference materials. Determination of these PAHs was achieved after clean-up by several chromatographic steps including fractionation on a modified TABA-silica gel column. Quantitative data for matrices such as two cigarette smoke condensates, motor vehicle exhaust condensate (Otto-type engines), and tar-cork are reported. Based on toxic equivalent factors the relative contribution of dibenzo[a,l]pyrene (5.4–42.3%) to the total carcinogenic activity of a PAH profile will be discussed comprising 14 selected isomers (benzo[b]naphtho[2,1-d]thiophene; cyclopenta[cd]pyrene; benz[a]anthracene; chrysene/triphenylene; sum of benzo[b]-, benzo[k]-, and benzo[j]fluoranthene; benzo[a]pyrene; indeno[1,2,3-cd]pyrene; dibenz[a,h]anthracene; benzo[ghi]perylene; anthanthrene; dibenzo[a,l]pyrene determined in these matrices.     

New Synthetic Approaches to PAHs and their Carcinogenic Metabolites

Syntheses of sterically crowded derivatives of benzo[ s ]picene and naphtho[1,2,3,4- rst ]pentaphene and their bis -dihydrodiol metabolites via a method that involves in the key steps double Suzuki coupling of aryl bis -boronic acid and o -bromoaryl aldehyde precursors are described.     

3-[3-(1-哌啶甲基)苯氧基]丙胺的合成工艺改进

以间羟基苯甲醛为起始原料,经由氧烷基化、缩合、水解得3-[3-(1-哌啶甲基)苯氧基]丙胺,收率49．1％,结构经NMR确证。     

Relationship Between Inhaled PAH and Urinary Excretion of Phenanthrene,Pyrene and Benzo[a]pyrene Metabolites in Coke Plant Workers

Abstract

By means of personal air samplers the exposure to polycyclic aromatic hydrocarbons (PAH) of four coke employees working at different locations was measured during 4 running days. Simultaneously the 24 hrs urines were collected. A simple, well reproducible method for the determination of 9,10-dihydroxy-9,10-dihydrobenzo[a]pyrene, 1-; 2-; 3-; 4- and 9-hydroxyphenanthrenes, 1,2-; 3,4-; and 9,10-dihydroxydihydrophenanthrenes as well as 1-hydroxypyrene and 1,2-dihydroxy-1,2-dihydropyrene was used. As expected, workers on the battery topside are most exposed and, accordingly, excrete by far the highest amount of PAH metabolites. A good correlation between the PAH inhaled during 8 hrs and the metabolites excreted in the 24 hrs urine is observed. 20% to 30% of the inhaled phenanthrene is excreted as dihydrodiols, but only 0.5% of the inhaled benzo[a]pyrene forms 9,10-dihydrodiol in the urine. The individual invariance of the metabolite profile of the isomeric phenols and dihydrodiols indicates a genetically caused enzyme pattern of oxygenases, which can or cannot be induced by exogenous factors. More investigations are necessary to clarify whether this metabolic profile may be suitable as a marker for carcinogenic risk.     

The Role of Cytochrome P450 1B1 in Dibenzo[ a,l ]pyrene-induced Carcinogenesis

In human cells, the most carcinogenic polycyclic aromatic hydrocarbon dibenzo[ a,l ]pyrene (DB[ a,l ]P) forms high levels of DNA adducts through formation of the ( m )- anti -(11 R ,12 S )-diol (13 S ,14 R )-epoxide (DB[ a,l ]PDE) and its metabolic precursor, the ( m )-(11 R ,12 R )-diol. Generation of these adducts results from the catalytic activity of cytochrome P450 (P450) 1A1 and 1B1. Additional adducts such as (+)- syn -DB[ a,l ]PDE-DNA or more polar DNA adducts were detected only after increasing exposure doses of the parent compound or in cells that express P450 1A1. At low concentrations (·;100 nM) exclusively ( m )- anti -DB[ a,l ]PDE-DNA adducts were formed by P450 1B1, which is constitutively expressed in many mammalian tissues. Measurement of DNA binding and mutagenicity of DB[ a,l ]P in V79 cells expressing human P450 enzymes revealed a higher activity of P450 1B1 compared to 1A1 at low concentrations. Treatment of P450 1B1 knockout mice and DNA binding studies with fibroblasts isolated from these animals provided further evidence for the central role of P450 1B1-catalyzed formation of ( m )- anti -DB[ a,l ]PDE-DNA adducts in DB[ a,l ]P-induced carcinogenesis.     

含环戊二烯络铁基团二苯并二噁英的合成

采用含环戊二烯络铁(FeCp)基团邻二氯苯和含羟基、巯基的二元酚类化合物合成含FeCp基团的二苯并二噁英.实验中,以N,N-二甲基甲酰胺(DMF)为溶剂,室温下,在K2CO3弱碱性介质中,产品收率高,副反应少,反应时间短.通过1H NMR和13C NMR对该类产品结构的研究表明产品纯度高;酚类的选择不同,H、C化学位移有一定差异.     

Comparison of N-Heterocyclic Aromatics Dibenzo[c,g]Carbazole and Dibenz[a,j]Acridine : Metabolism,DNA Binding and Mutation

N-Heterocyclic aromatics, such as carbazole and acridine derivatives, are environmental carcinogenic pollutants. Examples of these compounds are 7H-dibenzo[c,g]carbazole (DBC) and dibenz[a,j]acridine (DBA). The ionization potential (IP) for DBC is lower than for DBA. DBC is metabolized in lung and liver by way of phenols or directly through radical cations. DBC-induced liver and lung tumors have mutations in the 61^st codon of ras. DBA is metabolized in skin by way of a diol-epoxide of DBA. DBA-induced skin tumors have mutations in 12^th, 13^th and 61^st codons of ras. In summary, the metabolic activation of DBC proceeds through different adduction pattern pathways than does DBA and leads to different ras mutational spectra.     

2-氟-9,10-亚甲二氧基-6[H]-[1]苯并吡喃并[4,3-b]喹啉的合成与表征

以6-氟-色满酮-4为原料，与6-氨基胡椒醛发生Friedǎnder合反应而得到新的喹啉衍生物2-氟-9，10-亚甲二氧基-6[H]-[1]苯并吡喃并〔4，3-b]喹啉，其结构经IR、^1HNMR、MS和元素分析确证。     

Two-component,one-pot synthesis of pyrimido[1,2-b] [1,2,4,5]tetrazines

Derivatives containing the cyclohepta4′,5′thieno[2′,3′:4,5]pyrimido[1,2-b][1,2,4,5]-tetrazin-6-one system were prepared from the reaction of 3-amino-2-thioxo-1,2,3,5,6,7,8,9-octahydro-4H-cyclohepta[4,5]thieno[2,3-d]pyrimidin-4-one (5) or its 2-methylthio derivative 6 with hydrazonoyl chlorides 9. The mechanism of the studied reactions has been discussed and the biological activity of the isolated products has been evaluated.     

Synthesis of Adducts of PAH Diol Epoxide Metabolites in p53 Tumor Suppressor Gene Sites

The synthesis, structures, and mutagenic properties of benzo[a]pyrene-deoxyadenosine adducts in a sequence context related to the p53 gene are described.