Biphenyls, dichloro

PCBs and PCTs are particularly troublesome liquids because of their toxicity and persistence in the environment. They are defined as polychlorinated biphenyls, polychlorinated terphenyls, monomethyl-dibromo-diphenyl metliane, monomethyl-dichloro-diphenyl metliane or monomethyl-tetrachlorodiphenyl methane. With low electrical conductivity and heat resistance they found wide use as dielectric fluids and were formerly used as hydraulic fluids. PCBs have not been made in the UK since 1977 and whilst most new uses for the substance are banned in most countries, around two-thirds of the 1.5 million tonnes manufactured in Europe and the US prior to 1985 still remain in equipment such as transformers. PCTs have been used in the past in a restricted range of specialist industrial applications. 

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. 

The present method of preparation of 4,4 -dimethyl-l,l -biphenyl is that described by McKillop, Elsom, and Taylor 15 It has the particular advantages of high yield and manipulative simplicity and is, moreover, applicable to the synthesis of a variety of symmetrically substituted biaryls 3,3 - and 4,4 -Disubstituted and 3,3, 4,4 -tetrasubstituted 1,1 -biphenyls are readily piepared, but the reaction fails when applied to the synthesis of 2,2 -disubstituted-l,T biphenyls The submitters have effected the following conversions by the above procedure (starting aromatic bromide, product biphenyl, % yield) bromobenzene, biphenyl, 85,1 -bromo-4-methoxybenzene, 4,4 -dimethoxy-l, 1 -biphenyl, 99, 1 bromo 3 methylbenzene, 3,3 dimethyl-1,l -biphenyl, 85 4-bromo-l,2-dimethylbenzene, 3,3, 4,4 -tetramethyl-l,l -biphenyl, 76, l-bromo-4-chlorobenzene, 4,4 -dichloro-l,l -biphenyl, 73, l-bromo-4-fluorobenzene, 4,4 -difluoro-l,l -biphenyl, 73... 

Hay AG, DD Focht (1998) Cometabolism of l,l-dichloro-2,2-bis(4-chlorophenyl)ethylene by Pseudomomas acidovorans M3GY grown on biphenyl. Appl Environ Microbiol 64 2141-2146. 

Fig. 4 Scientific studies in sediments. HBCD hexabromocyclododecane PCBs polychlorinated biphenyls OCs organochlorine pesticides PCN polychlorinated naphthalene DDTs dichloro diphenyl trichloroethane...

Fig. 5 Scientific studies in biota. DDTs dichloro diphenyl trichloroethane HCB hexachlorobenzene HCHs hexachlorocyclohexanes OCs organochlorine pesticides OPs phosphorate pesticides PCBs polychlorinated biphenyls HBCD hexabromocyclododecane...

The idea of enantioselective activation was first reported by Mikami and Matsukawa111 for carbonyl-ene reactions. Using an additional catalytic amount of (R)-BINOL or (/ )-5.5 -dichloro-4,4, 6,fi -tctramcthyl biphenyl as the chiral activator, (R)-ene products were obtained in high ee when a catalyst system consisting of rac-BINOL and Ti(OPri)4 was employed for the enantioselective carbonyl ene reaction of glyoxylate (Scheme 8-54). Amazingly, racemic BINOL can also be used in this system as an activator for the (R)-BINOL-Ti catalyst, affording an enhanced level of enantioselectivity (96% ee). 

Fig. 16. Structure of a banana molecule 4,6-dichloro-l,3-phenylene bis[4 -(9-deceny-loxy)biphenyl] carboxylate and 13C NMR spectra in the nematic (top) and isotropic (bottom) phase.

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). 

Dichloro-biphenyl Frog 3-Hydroxy analog and other phenols Water Tissues 8... 

Synonyms BRN 2108022 CCRIS 220 C.I. 23060 Curithane C126 DCB 4,4 -Diamino-3,3 -di-chlorobiphenyl 4,4 -Diamino-3,3 -dichlorodiphenyl Dichlorobenzidine Dichlorobenzidine base m m -Dichlorobenzidine 3,3 -Dichloro-l,r-(biphenyl)-4,4 -diamine 3,3 -Dichlorobiphenyl-4,4 -diamine 3,3 -Dichloro-4,4 -biphenyldiamine 3,3 -Dichloro-4,4 -diaminobiphenyl 3,3 -Di-chloro-4,4 -diamino(l,1-biphenyl) EINECS 202-109-0 NSC 154073 RCRA waste number U073. 

Developer 13, see p-Phenylenediamine Developer P, see 4-Nitroaniline Developer PF, see p-Phenylenediamine Devicarb, see Carbaryl Devikol, see Dichlorvos Devol orange B, see 2-Nitroaniline Devol orange R, see 3-Nitroaniline Devol orange salt B, see 2-Nitroaniline Devol red GG, see 4-Nitroaniline Devoran, see Lindane Devoton, see Methyl acetate Diacetone, see Diacetone alcohol Diacetonyl alcohol, see Diacetone alcohol Diakon, see Methyl methacrylate Dialene 6, see 1-Hexene 1,4-Diaminobenzene, see p-Phenylenediamine p-Diaminobenzene, see p-Phenylenediamine 4-Diaminodiphenyl, see Benzidine p-Diaminodiphenyl, see Benzidine 4,4 Diaminobiphenyl, see Benzidine p,p -Diaminobiphenyl, see Benzidine 4,4 -Diamino-l,l -biphenyl, see Benzidine 4,4 -Diamino-3,3 -dichlorobiphenyl, see 3,3 -Dichloro-benzidine... 

Dichloro-2-chloroethylene, see Trichloroethylene 3,3 -Dichloro-4,4 -diamino-(l,1-biphenyl), see 3,3 -Di-... 

Synonym(s) Dichlorobenzidine 3,3 -dichloro(1,1 -biphenyl)-4,4 -diamine 3,3 -dichloro-4,4 - Merck 1989... 

Since the publication of CHEC-II(1996), there have been very few examples related to the reactivity of substituents attached to ring carbon atoms. One case involves the reaction of 3-benzylidene-2,3-dihydro-2-methyl-l,2-benzothiazin-4-one 1,1-dioxide 163 with the alkylidenephosphorane derived from salt 164 forming the tricyclic-fused ring compound 165 (Scheme 20) <1996J(P1)2541>. This material 165 was oxidized with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) affording the biphenyl 166. Ring-opened product 167 was produced from 165 upon exposure to />-toluene-sulfonic acid and heat. 

DDD Dichloro(chlorophenyl)-bis Ethane DDE Dichlorodiphenyldichloroethylene Dichlorobenzene, 1,2 Dichlorobenzene, 1,3 Dichlorobenzene, 1,4 Hexachlorobenzene Polychlorinated Benzenes Polychlorinated Biphenyls PCBs Aroclor Ring-Substituted Aromatics Tetrachlorobenzene Trichlorobenzene, 1,2,4 Saturated Alkyl Halides Bromodichloromethane Bromoform Tribromomethane Butyl Chloride Chlorobutane Carbon Tetrachloride Carbon Tetrafluoride Chloroform Trichloromethane Chloromethane Methyl Chloride Dibromochloromethane Dibromoethane, 1,2 Ethylene Dibromide Dibromomethane... 

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