L- - -bromide

In a 500 ml. bolt-head flask provided with a thermometer (reaching almost to the bottom) and a calcium chloride (or cotton wool) guard tube, place 100 g. of a-bromo-wo-valerj l bromide and 50 g. of dry, finely-divided urea. Start the reaction by warming the flask on a water bath the temperature soon rises to about 80°. Maintain this temperature for about 3 horns the mass will liquefy and then resolidify. Transfer the sticky reaction product to a large beaker containing saturated sodium bicarbonate solution, stir mechanically and add more saturated sodium bicarbonate solution in small quantities until effervescence ceases. Filter at the pump, suck as dry as possible and dry the crude bromural upon filter paper in the air. RecrystaUise the dry product from toluene. Alternatively, recrystaUise the moist product from hot water (ca. 700 ml.). The yield of pure brommal, m.p. 154-155°, is 28 g. 

After the air in the flask had been replaced completely with nitrogen, 100 ml of dry diethyl ether, 0.20 mol of the cumulenic ether (see Chapter V, Exps. 7, 8 and 11) and 1 g (note 1) of copper(l) bromide were placed in it. A solution of the Grignard-reagent, prepared from 0.50 mol of the chloride (see Chapter II,... 

Sandmeyer reaction using cop per(l) bromide is applicable to the conversion of primary arylamines to aryl bromides... 

Diazotization of a primary arylamine followed by treatment of the diazo mum salt with copper(l) bromide or copper(l) chloride yields the corre spending aryl bromide or aryl chloride... 

Typical brines received at an Arkansas bromine plant have 3—5 g/L bromide, 200—250 g/L chloride, 0.15—0.20 g/L ammonia, 0.1—0.3 g/L hydrogen sulfide, 0.01—0.02 g/L iodide, and additionally may contain some dissolved organics, including natural gas and cmde oil. The bromide-containing brine is first treated to remove natural gas, cmde oil, and hydrogen sulfide prior to introduction into the contact tower (48). 

The approximate composition of surface water in the Dead Sea in 1966 (49) was given as 35 g/L calcium chloride 130 g/L magnesium chloride nearly 80 g/L sodium chloride more than 10 g/L potassium chloride nearly 4 g/L bromide and about 1 g/L sulfate. At 400 m depth the bromide concentration was 6 g/L. Bromine in Israel is produced from the Hquors left from potash production and the bromide content of these Hquors is 14 g/L. 

Perfluoroacetylentc copper compounds also can be prepared via metathesis of the corresponding zinc or cadmium reagents with copper(l) bromide. The zinc or cadmium reagents are formed from the corresponding pentachloroperfluo-roalkaneorl lodoperfluoroalkyne [727 747] (equations 168 and 169)... 

Gill CO, C Ratledge (1972) Toxicity of -alkanes, -alkenes, -alkan-l-ols and -alkyl-l-bromides towards yeasts. J Gen Microbiol 72 165-172. 

Scheme 2.7. Preparation of functionalized arylcoppers from a l bromides.

Haddleton DM, Crossman MC, Dana BH et al. (1999) Atom transfer polymerization of methyl methacrylate mediated by alkylpyridylmethan-imine type ligands, copper(l) bromide, and alkyl halides in hydrocarbon solution. Macromolecules 32 2110-2119... 

Commercial copper bromide or its dimethyl sulfide complex contains impurities that are deleterious to the reaction. Therefore, the copper(l) bromide-dimethyl sulfide complex is prepared according to the method of House from copper(l) bromide generated by reduction of copper(ll) bromide (Aldrich Chemical Company, Inc., 99%) with sodium sulfite. Best results ctre obtained using copper(l) bromide-dimethyl sulfide complex freshly recrystallized according to the following procedure. 

A 100-mL conical flask equipped with a condenser and a nitrogen inlet is charged with copper(l) bromide-dimethyl sulfide complex (15 g). Anhydrous dimethyl sulfide (50 ml) is added via syringe and the mixture heated gently until all the solid dissolves. The heating bath is removed and pentane (25 mL) is added to the warm solution. The solution... 

This approach to C (1) nucleophiles has been recently extended. The Lichten-thaler zinc enolate reacts efficiently with more demanding aldehyde electrophiles to provide C-disaccharides [108,109], and activation of the C(l) bromide 276 can also be carried out using CeCl3/NaI (Scheme 72). The latter method is based on the earlier work of Ftdcuzawa [110] and others [111], although the mechanism of this cerium-mediated reaction has yet to be fully understood. 

Terminal allenes.1 Terminal acetylenes can be converted by a one-step reaction into terminal allenes by treatment with formaldehyde, diisopropylaminc, and copper(l) bromide in refluxing THF or dioxane. The Mannich base is an intermediate, but, surprisingly, preparation of the quaternary base is not necessary. The source of the introduced hydrogen is not clear. The highest yields are obtained with 2-propynylic alcohols, ethers, and esters. 

Experimental Procedure 10.1 Arylalion ol bcn/ylamine with a support-bound an l bromide [821... 

Wiberg and McMurdie have prepared bicyclo[1.1.0]butyl-l-carbinyl cation 13 by the ionization of bicyclo[l.l.l]pentyl-l-bromide with SbFother derivatives give products derived from the intermediacy of 3-methylenecyclobutyl cation 14, rather than the bicyclobutylcarbinyl cation (equation 22). In nucleophilic solvents, solvent... 

The structure of copolymers obtained by ATRP copolymerization of 5,6-benzo-2-methylene-l,3-dioxepane (BMDO) with H-butyl acrylate ( BA) using ethyl 2-bromoisobutyrate and iV,iV,iV, iV ,iV -pentamethyldiethylenetri-amine/copper(l) bromide, as the initiator and catalyst, respectively, was studied by ID and 2D NMR techniques, which revealed a quantitative ring opening of BMDO in the copolymerization <2005PLM11698>. For a similar study of copolymers of BMDO and styrene, see <2003MM6152>, and with methyl methacrylate, <2003MM2397>. 

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