Polychloro aromatics

This and other metallations of polyfluoro ° and polychloro aromatics are aided by the strongly electron-withdrawing halogens. 

M. Ballester and S. Olivella, Aromatic and Alkaromatic Chlorocarbons in Polychloro-aromatic Compounds, H. Suschitzky, (ed). Plenum Press, London, 1974, 6. 

Several reviews have been published on electrophilic homocyclic and heterocyclic aromatic substitution. Other reviews and books of relevance include polychloro-aromatic compounds, annulenes and related compounds, cyclobutadiene-metal complexes/ substitution via heteroaromatic N-oxide rearrangements/ 7T-excessiveness in heteroaromatic compounds/ and special topics in heterocyclic chemistry. The book by Jones and Bean is a mine of information on pyrrole chemistry. ... 

Benzene monoxide-oxepin and its sulfur analog are treated elsewhere (Chapter 5.1.7) (67AG(E)385). However, we point out here that electron-withdrawing substituents often favor the benzene oxide tautomer. The first study on oxides of the environmentally hazardous polychloro- and polybromo-biphenyls shows that they exist mainly in the benzene oxide form (81JOC3721). Oxides of polynuclear aromatic hydrocarbons (PAH) also exist mainly in the fused-ring oxirane form. 

Fig. 26. Evolution of the T-peel strength of roughened styrene-butadiene rubber/polychloro-prene-aromatic hydrocarbon resin blends as a function of the resin content. Peeling rate = 10 cm/tnin.

Aromatic fluorodenitration was first discovered in the reaction of polychloro-nitrobenzenes with potassium fluoride, when 2,3,5,6-tetrachlorofluorobenzene was prepared in 37% yield from 2,3,5,6-tetrachloronitrobenzene 105] The technique has been adapted to prepare aryl fluorides from other activated nitro aromatics for applications in pharmaceutical and polymer chemistry (equation 31) Fluorodenitration also has been applied to prepare radiolabeled ( F) fluo-roaromatics [74, 106]... 

Industrial workers involved in chlorinated aromatic production including chlorophenol suffered dioxin-induced chloracne 2,3). Chloracne and other serious health disturbances have been attributed to polychloro-dibenzo-p-dioxins in workers involved in manufacturing 2,4,5-T 4, 5). Dioxins are toxic to chick embryos, guinea pigs, rabbits, and monkeys 6, 7, 8, 9, 10). 

Oxygen substitution reactions occur for many halogenated compounds and for aromatic hydrocarbons. The best known reactions are those of aromatic polychloro and nitrochloro compounds (6). 

Baker, J.E., S.J. Eisenreich, and B.J. Eadie. 1991. Sediment trap fluxes and benthic recycling of organic carbon, polycyclic aromatic hydrocarbons, and polychloro-biphenyl congeners in Lake Superior. Environ. Sci. Technol. 25 500-509. 

Other more common aromatic or cyclic chlorinated compounds were found under various trademarks are 4,4 -dichloro-3,3 -trifluoromethyl diphenylurea (Mitin LP, Ciba-Geigy) N-5-chloro-2-(2-sulfo-4-chlorophenyl-N -3, 4 -dichlorophenyl urea, (Mitin FF), polychloro-2-(chloromethylsulfonamido)-diphenyl ethers, [Pg.287]

The ozone induced reaction of polychloro benzenes and some related halogeno compounds with nitrogen dioxide is a novel non-acid methodology for the selective mono nitration of moderately deactivated aromatic systems [100]. In the presence of ozone and preferably with methanesul-fonic acid as a catalyst, the polychloro benzenes undergo mononitration... 

Jiang, Z.Q., Marquet, J., Cervera, M., and GaUardo, I., Reductivity activated polar nucleophilic aromatic substitution. 4. Thermal and photochemical behavior of polychloro and polyfluoroni-trobenzenes in front of soft nucleophiles. An. Quim. Int. Ed., 92, 95,1996. 

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