2,4,3’,4’-Tetrachloro-1,1’-biphenyl

Some PCB congeners have coplanar structures (see, e.g., 3,4,3, 4 -tetrachloro-biphenyl in Figure 6.1). The coplanar conformation is taken up when there is no chlorine substitution in ortho positions. If there is substitution of chlorine in only one ortho position, the molecule may still be close to coplanarity, because of only limited interaction between Cl and H on adjoining rings. Substitution of chlorines in... 

Brunstrom, B. and P.O. Damerud. 1983. Toxicity and distribution in chick embryos of 3,3, 4,4 -tetrachloro-biphenyl injected into the eggs. Toxicology 27 103-110. 

Radioactivity levels were elevated in uterine fluid and in fetuses in late gestation. No unmefabolized PCB 77 was detected in fetuses, but PCB 77 metabolites (including 3,3, 4,4 -tetrachloro-2-biphenylol, and methylsulphonyl-tetrachloro-biphenyl) were found in fetuses in late gestation... 

Asmus and co workers81 studied the pulse radiolysis of polychlorinated biphenyls (PCB) in N2-saturated DCE solutions. The transient absorption spectrum at 5 /is after a 1 /is pulse showed either two distinct absorption maxima (as, e.g., for 3,3, 4,4 -tetrachloro-biphenyl) or a broad absorption band (in the case of 2,2, 4,4, 5,5 -hexachlorobiphenyl) or a broad maximum with an additional shallow shoulder (for 3,5-dichlorobiphenyl) in the range of 375 130 nm. It appears that the number and position of chlorine substituents determine the absorption category. Another absorption band was indicated in the near IR region, but could not be studied. The observed absorption in the 375-430 nm range is attributed to the radical cations from PCB, formed by charge transfer from the radical cation of the solvent ... 

Polychlorinated biphenyls (PCBs) and dioxins are also of special interest. The biphenyl group is able to serve some microorganisms as their carbon and energy source, and thus the mono-, di-, tri-, and tetrachloro biphenyls are, to some degree, subject to biodegradation. However, in more extensively chlorinated biphenyls, the substituents prevent ring hy-droxylation. See Figure 9.14. 

Figure 13. Synthesis of 4-methylthio-2,2, 5,5 -tetrachloro-biphenyl via nucleophilic aromatic substitution.

Brouwer, A., and K. J. van den Berg. 1996. Binding of a metabolite of 3,4,3, 4 -tetrachloro-biphenyl to transthyretin reduces serum vitamin A transport by inhibiting the formation of the protein complex carrying both retinol and thyroxin. Toxicology and Applied Pharmacology 85 301-312. 

Venkatachalam, K., Arzuaga, X., Chopra, N., Gavalas, V.G., Xu, J., Bhattacharyya, D., Heimig, B. and Bachas, L.G. 2008. Reductive dechlorination of 3,3, 4,4 -tetrachloro-biphenyl (PCB77) using palladium or palladium/iron nanoparticles and assessment of the reduction in toxic potency in vascular endothelial cells. J. Hazard. Mater. 159(2-3) 483-191. 

Mutagenicity Chromosomal abnormalities negative Dominant lethal mutations negative Ames test 1221, tetrachloro biphenyl significantly mutagenic. 

Ultraviolet sources of >290 nm are being increasingly used to simulate natural sunlight. Irradiations have been conducted in gas, solution, and solid phases to create results comparable to natural environmental conditions. Hustert and Korte (1972) showed that gas-phase irradiations did not affect a hexachlorobiphenyl compound but formed polar products from a tetrachloro-biphenyl and water. Irradiation in the gas phase is especially relevant to LCBPs that are relatively volatile. 

Reaction of sodium methoxide with (147) does not give 2,3,4,5-tetrachloro-biphenyl as earlier reported in this study, (148) and (149) were obtained. In view of the failure of addition to styrene under similar reaction conditions it is likely that the chlorines activate the double bond to nucleophilic attack. With (150) two major products, (151) and (152), were found. The preference for attack at the double bonds is considered to be finely balanced. The suggestion of intermediate non-classical carbanions seems unlikely no tricyclic products are observed. In a detailed investigation, other polyhalogenonorbornadienes were observed to undergo similar vinylic substitution or addition. The products... 

Dioxins are prominent members of the class of polychlorinated hydrocarbons that also includes diben-zofuran, biphenyls and others. Dioxins are highly toxic environmental contaminants. Like others small planar xenobiotics, some dioxins bind with high affinity to the arylhydrocarbon (Ah) receptor. Dioxins activate the receptor over a long time period, but are themselves poor substrates for the enzymes which are induced via the Ah-receptor. These properties of the dioxins and related xenobiotics may be important for the toxicity of these compounds. Dioxins like 2,3,7,8-tetrachloro-p-dibenzodioxin can cause persistent dermatosis, like chloracne and may have other neurotoxic, immunotoxic and carcinogenic effects. 

Mizutani and coworkers57a confirmed the presence of polychloro(methylsulfonyl)biphenyls (159-170) as sulfur-containing metabolites of chlorobiphenyls (Cl-BP) in the feces of mice based on both GLC-mass spectrometry and chemical derivatization. In some cases comparison with authentic samples (161 and 162) was also made. When preparing 161 and 162,2,5-dichloro-3-(methylsulfonyl)aniline, 2,5-dichloro-l-iodo-3-(methylsulfonyl)benzene and 2,2, 5,5 -tetrachloro-3,3 -bis(methyl-sulfonyl)biphenyl were also obtained and their four peak El mass spectra reported572. Similar data were given for the corresponding 4-substituted intermediates, which were involved in the preparation of 162. Also 2,4, 5-trichloro-2 -(methylsulfonyl)-biphenyl was prepared and its four peak mass spectra given. Metabolites 163 and 164 were also identified by comparison with the authentic standards. 

Damerud, P.O., I. Brandt, E. Klasson-Wehler, A. Bergman, R. d Argy, L. Denker, and G.O. Sperber. 1986. 3,3, 4,4 -Tetrachloro[14C]-biphenyl in pregnant mice enrichment of phenol and methyl sulfone metabolites in late gestational fetuses. Xenobiotica 16 295-306. 

Smith, L.S., T.R. Schwartz, K. Felz, and T.J. Kubiak. 1990. Determination and occurrence of AHH-active polychlorinated biphenyls, 2,3,7,8-tetrachloro-/>-dioxin and 2,3,7,8-tetrachlorodibenzofuran in Lake Michigan sediment and biota. The question of their relative toxicological significance. Chemosphere 21 1063-1085. 

NP NPEC OC OP OPEC PCB PCDBT PCDD PCDF PCP PFB RA TCA TCDD TCF TCMTB TOC VSC VOC Nonylphenol Nonylphenol ethoxycarboxylate Organo chlorine Octylphenol Octylphenol ethoxycarboxylate Polychloroinated biphenyls Polychlorinated dibenzothiophene Polychlorin ated dib enzo-p - dioxins Polychlorinated dibenzo-p-furans Pentachlorophenol Pentafluorobenzyl Resin acids 2,4,6-Trichloroanisole Tetrachloro dibenzo dioxin Totally chlorine- free 2-(Thiocyanomethylthio)-benzothiazole Total organic carbon Volatile sulphur compounds Volatile organic compounds... 

Along with degree of chlorination another determinant of PCB metabolism in fish is species. Green sunfish and goldfish rapidly metabolize 2,2, 5-trichlorobiphenyl whereas bullheads and rainbow trout metabolize it slowly (26,29). There is little evidence for PCB metabolism in brook trout fed 4-chloro-, 4,4 -dichloro-, 2,2, 5,5 -tetrachloro- or 2,2, 4,4, 5,5 -hexachloro-biphenyl (31) and this was confirmed in rainbow trout by less than 1% of 2,2, 5,5 -tetrachlorobiphenyl accumulated being recovered as polar metabolites (25). 

Source Hexachlorobenzene may enter the environment from incomplete combustion of chlorinated compounds including mirex, kepone, chlorobenzenes, pentachlorophenol, PVC, polychlorinated biphenyls, and chlorinated solvents (Ahling et al., 1978 Dellinger et al., 1991). In addition, hexachlorobenzene may enter the environment as a reaction by-product in the production of carbon tetrachloride, dichloroethylene, hexachlorobutadiene, trichloroethylene, tetrachloro-ethylene, pentachloronitrobenzene, and vinyl chloride monomer (quoted, Verschueren, 1983). 

Common Name 2,2, 3,6-Tetrachlorobiphenyl Synonym PCB-45, 2,2, 3,6-tetrachloro-l,l -biphenyl Chemical Name 2,2, 3,6-tetrachlorobiphcnyl CAS Registry No 70362-45-7 Molecular Formula C12H6C14 Molecular Weight 291.988 Melting Point (°C) ... 

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