Dimethyl benzanthracene

Liver cancer can also be a consequence of exposure to hepatotoxic chemicals. Natural hepatocarcinogens include fungal aflatoxins. Synthetic hepato-carcinogens include nitrosoamines, certain chlorinated hydrocarbons, polychlorinated biphenyls (PCBs), chloroform, carbon tetrachloride, dimethyl-benzanthracene, and vinyl chloride.Table 5.15 lists the chemical compounds that induce liver cancer or cirrhosis in experimental animals or... 

Figure 6.10. Rate constants for quenching of sensitizers by cis- and trans-stilbenes (open and filled circles, respectively). Sensitizers are as follows (1) tri-phenylene, (2) thioxanthone, (3) phenanthrene, (4) 2-acetonaphthone, (3) 1-naphthyl phenyl ketone, (6) crysene, (7) fluorenone, (8) 1,2,5,6-dibenzanthracene, (9) benzil, (10) 1,2,3,4-dibenzanthracene, (11) pyrene, (12) 1,2-benzanthracene, (13) benzanthrone, (14) 3-acetyl pyrene, (15) acridine, (16) 9,10-dimethyl-l,2-benzanthracene, (17) anthracene, (18) 3,4-benzpyrene.<57> Reprinted by permission of the American Chemical Society.

Synonym 7,12-dimethylbenz [a]anthracene, 9,10-dimethyl-1,2-benzanthracene, 7,12-dimethylbenzanthracene... 

Miproxifene (TAT-59) is a prodrug of 4-hydroxy-tamoxifen that has been developed for tamoxifen-resistant carcinoma, but relatively little information has been published on this drug. Compared with tamoxifen, miproxifene inhibits estradiol-stimulated proliferation of MCF-7 cells at a threefold lower dose than that of tamoxifen, and of dimethyl-benzanthracene (DMBA)-induced rat mammary tumors at a dose tenfold lower than tamoxifen (Toko et al. 1990). In any event, in preclinical castrated rat models, it shows an endometrial stimulation activity that is similar to that of tamoxifen, which means it has limited potential use in the prevention or treatment of osteoporosis or cardiovascular disease (Shibata et al. 2000). Similarly, considering the preclinical findings of endometrial stimulation reported on GW5638 (Willson et al. 1997), it is likely that this new SERM belonging to the triphenylethylene family will be limited in clinical use to the treatment of advanced tamoxifen-resistant breast cancer once its efficacy is demonstrated in human clinical trials. 

Procedure for the Chinese Hamster V79/Hgprt Assay. The assay usually comprises three test concentrations, each in duplicate, and four vehicle control replicates. Suitable positive controls are ethylmethane sulphonate (—S9) and dimethyl benzanthracene (+S9). V79 cells with a low nominal passage number should be used from frozen stocks to help minimize genetic drift. The procedure described includes a reseeding step for mutation expression. 

Gwynn and Salaman H tested a number of compounds, Including CN, as possible promoters of skin carcinogenesis when 9,10-dimethyl-1,2-benzanthracene (DMBA) was used as an initiator. Treatment consisted of 0.3 ml of a 0.1% or 0.15% acetone solution of DMBA on the clipped backs of mice, followed after a delay of 21 d by application of CN at a maximal tolerated concentration once or twice a week for 12-15 wk. There was a significant increase in tumors 22 wk after the start of secondary treatment. 

These alternatives may be distinguished by examining the concentration dependence of the molecular fluorescence yield given by Eq. (1) the observation of self-quenching invalidates condition (b) and provides strong evidence for photoassociation in systems where qD 0. These criteria are applied to the behavior of anthracene and certain of its derivatives in Table V, from which it is concluded that photoassociation of 9,10-diphenyl-anthracene (as in 9,10-dimethyl-1,2-benzanthracene and rubrene) is prohibited by steric hindrance of the bulky substituents (Table III). 

Additions to Aromatic Hydrocarbons. A variety of photochemical additions to aromatic hydrocarbons have been reported. Benzene and its derivatives add to maleic anhydride74-76 as well as to simple olefins,77-80 isoprene,81 acetylene derivatives,79,82 and alcohols.83 The mechanism of the maleic anhydride-benzene reaction is discussed in Section IV. A.4. Naphthalene forms a photoadduct with dimethyl acetylenedicarboxylate62 and with acrylonitrile8211 while anthracene behaves similarly with maleic anhydride84 and with 1,2-benzanthracene.85 The photoaddition of several aromatic amines to anthracene has been reported to proceed via a charge transfer complex86,87 in fact, the majority of these addition reactions may proceed in this manner. 

Goerttler, K. and Laehrke, H. (1976). "Diaplacental carcinogenesis initiation with the carcinogens dimethyl-benzanthracene (DMBA) and urethane during fetal life and postnatal promotion with the phorbol ester TPA in a modified 2-stage BerenblumyMottram experiment, Virch. Arch. Path. Anat. HistoL 372,29. 

Another health hazard associated with exposure to UV radiation is the potential cocarcinogenic activity of UV light with the contaminant on the skin. Past studies have found that exposure to UV radiation results in a significant enhancement of the effects of chemical carcinogens such as 7,12-dimethyl benzanthracene (13) and benzo[a]pyrene (14). Even normally innocuous compounds such as anthracene, n-decane and n-tetradecane can develop tumorigenic activity in mice under irradiation with long-wavelength (>350 nm)... 

Fia. 14. 9,10-Dimethyl-1,2-benzanthracene showing the displacements (10-3 A) of the carbon atoms from the mean plane through rings A, B, and C (Iball, 1962). 

Free dihydrodiol metabolites have been isolated from urine, following the administration of phenanthrene119 and chlorobenzene.120 The yields are low because, under mildly acidic conditions and gentle heating, the diols are easily dehydrated to phenols, or their D-glucuronic conjugates may be hydrolyzed and the aglycons reduced to the parent hydrocarbons. As a consequence, labile diols may be the true excretion products of many hydrocarbons whose phenolic derivatives have been isolated from urine, such as 1,2,5,6-dibenzanthracene, 1,2-benzanthracene, 3,4-benzopyrene, and 9,10-dimethyl-l,2-benzanthracene.121... 

In five of six nondietary tumor-promotion experiments, sodium selenide significantly reduced the number of mice with tumors induced by 7,12-dimethyl-benzanthracene (DMBA)-croton oil (1). In these experiments, sodium selenide was applied concomitantly along with croton oil to female Swiss albino mice initiated with DMBA. Riley has also observed a reduction in DMBA-phorbol ester carcinogenesis by sodium selenide (2). The effect of selenium-deficient and selenium-adequate diets on DMBA-croton oil and benzopyrene skin carcinogenesis has also been studied. Supplemental dietary selenium inhibited both types of carcinogenesis. 

It is noteworthy that l,3-dimethylnaphtho[l,2-c]thiophene (1,3-dimethyl-4,5-benzisothianaphthene in the literature) (67) has been prepared its properties have been compared with those of the benzanthracene derivative (68).65... 

Sandin and Fieser developed an efficient synthesis of the potently carcinogenic 9,10-dimethyl-l,2-benzanthracene from 1,2-benzanthraquinone (1) involving addition of methyl Grignard reagent, reaction of the adduct (2) with hydriodic acid to give the 9-methyl-10-iodomethyl derivative (3) and reduction with stannous chloride in dioxane-hydrochloric acid. 

Schillaci M, Martin SE, Milner JA. 1982. The effects of dietary selenium on the biotransformation of 7,12-dimethyl-benzanthracene. MutatRes 101 31-37. 

Dietary pretreatment with DDT decreased the incidence of mammary tumors induced by dimethyl benzanthracene (21). Carcinogenicity of ethylene dibromide has been shown (18) to be increased by exposure to disulfiram. Induction of lung benzo(a)pyrene hydroxylase by carbaryl paralleled an Increase in lung tumors induced by benzo(a)pyrene (19). In the same experiments, pretreatment with toxaphene decreased the incidence of lung adenomas (19) and this correlated with the inhibition of lung benzo(a)pyrene hydroxylase. 

Dimethyl-1,2-benzanthracene. 7,12-Di-methylbem[a]anthracene 1,4-dimethyl -2,3-benzphenan-threne. CwHtt mol wt 256.33. C 93.71%, H 6.29%. Synthesis from o-(a-methyl-a-l-naphthyDtoluic acid New-... 

Hill, W.T., D.W. Stanger, A. Pizzo, B. Riegel, P. Shubik, and W.B. Wartman Inhibition of 9,10-dimethyl-l,2-benzanthracene skin carcinogenesis in mice by polycyclic hydrocarbons Cancer Res. 11 (1951) 892-897. Hiller, F.C., M.K. Mazumder, J.D. Wilson, PC. McLeod, and R.C. Bone Human respiratory tract deposition using multimodal aerosols J. Aerosol Sci. 13 (1982) 337-343. 

Klein, M. Introduction of skin tumors in the mouse with minute doses of 9,10-dimethyl-1,2-benzanthracene alone or with croton oil Cancer Res. 16 (1956) 123-127. 

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