O- bromobenzen

Fig. 5 Electrochemical reduction of aryl halides showing the variation of the apparent transfer coefficient with the scan rate. iodobenzene, O bromobenzene, V 1-iodonaphthalene, O 4-methyliodobenzene, at 298 K, iodobenzene at 329 K.

It is not surprising that in attempted AICI3 catalysis of the reaction between thiophenol and various lactones, considerable amounts of thianthrene were obtained from a side reaction (81JOC5163). A low yield of thianthrene itself was obtained by converting o-bromobenzene thiol into its copper derivative (66JOC4071), but a good yield of thianthrene-2,3,7,8-tetracarboxylic acid 83 was observed from a hot reaction between 84 with cuprous oxide in DMF (82MI5). The saturated o-chlorobenzene thiols, 85... 

CyH3Br2N3, 2,4-Dibromophenyldiazocyanide, 32B, 60 C7Hi,BrN3, o-Bromobenzene-anti-diazocyanide, 37B, 28 C7HgBrN30, o-Bromophenylazocarbamide, 37B, 28... 

The following liquids may be used (boiling points are given in parentheses) — chlorobenzene (132-3°) bromobenzene (155°) p cymene (176°) o-dichloro-benzene (180°) aniline (184°) methyl benzoate (200°) teti-alin (207°) ethyl benzoate (212°) 1 2 4-trichlorobenzene (213°) iaopropyl benzoate (218°) methyl salicylate (223°) n-propyl benzoate (231°) diethyleneglycol (244°) n-butyl benzoate (250°) diphenyl (255°) diphenyl ether (259°) dimethyl phth ate (282°) diethyl phthalate (296°) diphenylamine (302°) benzophenone (305)° benzyl benzoate (316°). 

Nitration of bromobenzene with mixed acid yields largely p-bromo nitrobenzene accompanied by a little of the o-isomeride ... 

Nitration using this reagent was first investigated, by Francis. He showed that benzene and some of its homologues bromobenzene, benzonitrile, benzoyl chloride, benzaldehyde and some related compounds, and phenol were mono-nitrated in solutions of benzoyl nitrate in carbon tetrachloride anilines would not react cleanly and a series of naphthols yielded dinitro compounds. Further work on the orientation of substitution associated this reagent with higher proportions of o-substitution than that brought about by nitric acid this point is discussed below ( 5.3.4). 

Partial rate factors may be used to estimate product distributions in disubstituted benzene derivatives The reactivity of a particular position in o bromotoluene for example is given by the product of the partial rate factors for the corresponding position in toluene and bromobenzene On the basis of the partial rate factor data given here for Fnedel-Crafts acylation predict the major product of the reaction of o bromotoluene with acetyl chlonde and aluminum chloride... 

Salicyl-u-toluide has been prepared only by the action of phosphorus oxychloride upon a mixture of salicylic acid and o-toluidine. The useful methods of preparation of salicylanilide are by the interaction of salicylic acid and aniline in the presence of phosphorus trichloride, by heating phenyl salicylate and aniline, and from o-hydroxybenzamide and bromobenzene in the presence of small amounts of sodium acetate and metallic copper. A number of these and other anilides have been described. ... 

Our group suppressed (ref. 19) the deactivation by HBr by the addition of NaHC03 as a scavenger for HBr and zeolite KA for removal of water formed in the latter reaction. With these additives a p/o-selectivity of 97/3 was achieved in the bromination of bromobenzene over CeY. 

Finally we mention that aromatic bromides can be debrominated by hydrogen and a metal(o)-in-zeoite system (ref. 33). Over e.g. Cu(0)-Y bromobenzene is converted into benzene whereas over Pt-H-beta (200 °C) quantitative hydrodebromination is followed by hydrogenation and isomerization towards methylcyclopentane (Fig. 12). In this way undesired aromatic bromides can be recycled. 

Chlorobromobenzene has been prepared by the diazotiza-tion of o-bromoaniline followed by replacement of the diazonium group by chlorine 1 by the elimination of the amino group from 3-chloro-4-bromoaniline 2 by the chlorination of bromobenzene in the presence of thallous chloride,3 aluminum chloride,4 or ferric chloride 4 by the bromination of chlorobenzene without a catalyst6 or in the presence of aluminum,4 iron,4 or ferric bromide 6 by the diazotization of o-chloroaniline followed by replacement of the diazonium group with bromine 4,6 and from o-chlorophenylmercurie chloride by the action of bromine.7... 

Similarly, benzene and hydrazoic acid in the presence of a mixture of fluorosulphonic and trifluoromethanesulphonic acid give aniline quantitatively. From toluene 100% of a mixture of o-, m- and p-toluidines is obtained and bromobenzene yields 42% o-bromoaniline and 47% p-bromoaniline, Butyl azide gives iV-butylarylamines under these conditions89. Photolysis of 1-aminoquinolinium perchlorate (76) in aromatic hydrocarbons (benzene, toluene, ethylbenzene or mesitylene) in the presence of 18-crown-6 affords arylamines, e.g. aniline and p-toluidine, by way of the nitrenium ion90 cf Reference 91. 

Nickel(O) triphenylphosphine can be used to couple aryl halides and alkenes to synthesize substituted olefins [149], 1,2-bis[(di-2-propylphosphino)benzene]nick-el(0) can be used to couple aryl halides [150], and l,2-bis[(diphenylphos-phino)ethane]nickel(0) can be used to prepare benzoic acid from bromobenzene in the presence of carbon dioxide [151]. 

TRINITROBENZENE m-DIBROMOBENZENE m-CHLORONITROBENZENE o-CHLORONITROBENZENE p-CHLORONITROBENZENE tn-D I CHLOROBENZENE o-DICHLOROBENZENE p-DI CHLOROBENZENE m-DIFLUOROBENZENE o-DIFLUOROBENZENE p-DIFLUOROBENZENE m-DI NITROBENZENE o-DINITROBENZENE p-DINITROBENZENE BROMOBENZENE MONOCHLOROBENZENE m-CHLOROPHENOL o-CHLOROPHENOL p-CHLOROPHENOL... 

Chemical/Physical. Bromobenzene will not hydrolyze to any reasonable extent. In the laboratory, no change in concentration was observed after 29 d at 85 °C in O.IM NaOH and O.IM HCl (Kollig, 1995). 

BRN 1912585, see Hexachlorobenzene BRN 1912384, see 2,4-Dinitrotoluene BRN 1913355, seep,p -DDE BRN 1914064, see Di-fl-butyl phthalate BRN 1914072, see p,p -DDD BRN 1915474, see Chlordane BRN 1915994, see Di-fl-octyl phthalate BRN 2049930, see Naled BRN 2051258, see Pindone BRN 2052046, see 2,6-Dinitrotoluene BRN 2054389, see 4,6-Dinitro-o-cresol BRN 2055620, see 2,4,5-T BRN 2057367, see Methoxychlor BRN 2059093, see Parathion BRN 2062204, see Benzyl butyl phthalate BRN 2215168, see Diuron BRN 2542580, see EPN BRN 2807677, see 2-Acetylaminofluorene BRN 3195880, see a-BHC BRN 3196099, see Camphor BRN 3910347, see cis-Chlordane, frans-Chlordane Brocide, see 1,2-Dichloroethane Brodan, see Chlorpyrifos Bromchlophos, see Naled Bromex, see Naled Bromic ether, see Ethyl bromide Bromobenzol, see bromobenzene 4-Bromobiphenyl ether, see 4-Bromophenyl phenyl ether 4-Bromodiphenyl ether, see 4-Bromophenyl phenyl ether p-Bromodiphenyl ether, see 4-Bromophenyl phenyl ether Bromoethane, see Ethyl bromide Bromofluoroform, see Bromotrifluoromethane Bromofume, see Ethylene dibromide Brom-o-gaz, see Methyl bromide Bromomethane, see Methyl bromide Bromomethyl chloride, see Bromochloromethane... 

The starting acetylenic substrates are prepared by the Pd +-induced coupling of the alkynes with the appropriate o-substituted bromobenzenes. ... 

Yoshida et al. [63] applied microreaction technology for the sequential synthesis and the disubstitution of o-bromophenyUithiuni (Scheme 28). Lithiation of o-dibromobenzene in batch leads to the formation of the highly reactive benzyne and to the further creation of various side products thus this reaction needs to be conducted at 100°C and below to avoid this problem. This reaction was optimized under microreactor conditions for the production of o-bromophenyUithium and for its further reaction with methanol to determine the yield of bromobenzene. Microreactors were set up of stainless steel tubes with an internal diameter of 250-1,000 pm. 

Fio. 10. Effect of pressure programming on chromatographic separation. Stationary phase, nitrobenzyl-silica, SI 200 d, 35 /tm column, 50 x 2 mm eluent, n-hepune, temp., 23 C. Sample components 1. unretained 2, bromobenzene 3, toluene 4, naphthalene 5, anthracene 6, brasan 7, o,A-[Pg.50]

The choice of an ionic liquid was shown to be critical in experiments with [NBuJBr (TBAB, m.p. 110°C) as a catalyst carrier to isolate a cyclometallated complex homogeneous catalyst, tra .s-di(ri-acetato)-bis[o-(di-o-tolylphosphino) benzyl] dipalladium (II) (Scheme 26), which was used for the Heck reaction of styrene with aryl bromides and electron-deficient aryl chlorides. The [NBu4]Br displayed excellent stability for the reaction. The recycling of 1 mol% of palladium in [NBu4]Br after the reaction of bromobenzene with styrene was achieved by distillation of the reactants and products from the solvent and catalyst in vacuo. Sodium bromide, a stoichiometric salt byproduct, was left in the solvent-catalyst system. High catalytic activity was maintained even after the formation of visible palladium black after a fourth run and after the catalyst phase had turned more viscous after the sixth run. The decomposition of the catalyst and the formation of palladium... 

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