Phenanthrene, carcinogenic

Know the meaning of polycyclic aromatic hydrocarbon, naphthalene, anthracene, phenanthrene, carcinogenic, graphite, fullerene. 

The purpose of this eornpuLer project is Lo examine several polynuclear aromatic hydrocarbons and to relate their electron density patterns to their carcinogenic activity. If nucleophilic binding to DN.A is a significant step in blocking the normal transcription process of DN.A, electron density in the hydrocarbon should be positively correlated to its carcinogenic potency. To begin with, we shall rely on clinical evidence that benzene, naphthalene, and phenanthrene... 

Dihydro-9,10-epoxyphenanthrene and related arene oxides are of considerable interest as carcinogens formed by polycyclic aromatic hydrocarbons in vivo.45 Phenanthrene oxide does not isomerize to the corresponding dibenzoxepin under thermal conditions. Photolysis of... 

Methods for the synthesis of the biologically active dihydrodiol and diol epoxide metabolites of both carcinogenic and noncarcinogenic polycyclic aromatic hydrocarbons are reviewed. Four general synthetic routes to the trans-dihydrodiol precursors of the bay region anti and syn diol epoxide derivatives have been developed. Syntheses of the oxidized metabolites of the following hydrocarbons via these methods are described benzo(a)pyrene, benz(a)anthracene, benzo-(e)pyrene, dibenz(a,h)anthracene, triphenylene, phen-anthrene, anthracene, chrysene, benzo(c)phenanthrene, dibenzo(a,i)pyrene, dibenzo(a,h)pyrene, 7-methyl-benz(a)anthracene, 7,12-dimethylbenz(a)anthracene, 3-methylcholanthrene, 5-methylchrysene, fluoranthene, benzo(b)fluoranthene, benzo(j)fluoranthene, benzo(k)-fluoranthene, and dibenzo(a,e)fluoranthene. 

This PAH is a common environmental contaminant. However, it is inactive as a carcinogen in animal tests (50. The trans-1,2-di-hydrodiol of triphenylene has been synthesized from phenanthrene by a route analogous to that employed for the preparation of BeP 9,10-dihydrodiol (48). Like the latter compound, epoxidation with per-acid affords a mixture of the anti and syn diol epoxides (Figure 9) (48,50). 

Benzo(c)phenanthrene (BcP) is exceptionally weak or inactive as a carcinogen in experimental animals (51). On the other hand, the bay region anti diol epoxide of BcP (14) exhibits high tumor initiating activity on mouse skin (65). 

Most carcinogenic PAHs contain the phenanthrene grouping in them (see Figure 2) and there are two important areas in these molecules that are often referred to in studies of PAH carcinogenesis. 

At first three K-region oxides were studied, those of DMBA (XI), BP (XII) and phenanthrene, the non-carcinogenic parent (XIII) the structures are shown in Figure 8. These epoxides, which were considered very reactive, were found to remain stable both in air and in the X-ray beam when in the crystalline state (82, 83). 

The carcinogenicity of PAH with relativelyTigh IP, such as benzo[c]phenanthrene, benz[a]anthracene, chrysene, 5-methyl chrysene and dibenz[a,h]anthracene (Table I), can be related to the formation of bay-region diol epoxides catalyzed by monooxygenase enzymes (j>). However, the most potent carcinogenic PAH have IP < ca. 7.35 eV. 

The pitch of coal tar is the black or dark brown amorphous residue that remains after the redistillation process. The volatiles contain a large quantity of lower molecular weight polycyclic hydrocarbons. As these hydrocarbons (naphthalene, fluo-rene, anthracene, acridine, phenanthrene) sublime into the air there is an increase of benzo(polycyclic hydrocarbons in the tar and in the fumes. Polycyclic hydrocarbons, known to be carcinogenic, are of this large molecular type. 

The K-region of a polycyclic aromatic hydrocarbon is typified by the 9,10-bond of phenanthrene. According to the Schmidt-Pullman electronic theory, an unsubstituted K-region is a requirement for carcinogenic activity see A. Pullman and B. Pullman, La Cancerisation par les Substances Chimiques et la Structure Moleculaire, Masson, Paris, 1955. 

A further dietary component which may potentiate the carcinogenic action of IV-nitrosamines is millet, which contains silica fibers (156), known to promote the carcinogenic action of ll-methyl-15-cyclo-penta[a]phenanthrene (157), and presumably of certain other carcinogens also. 

Reactions of K-region arene oxides derived from phenanthrene and 7,12-dimethylbenz[a] anthracene with nucleosides have been studied with a view to assessing the carcinogenicity of the products obtained.199... 

Polycyclic aromatic hydrocarbons, which are built of fused benzene rings, include naphthalene, anthracene, and phenanthrene. Some, such as benzo[a]pyrene, are carcinogens. Graphite, a common allotrope of carbon, consists of layers of planar,... 

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