Cupric Bromide

Reppe s work also resulted in the high pressure route which was estabUshed by BASF at Ludwigshafen in 1956. In this process, acetylene, carbon monoxide, water, and a nickel catalyst react at about 200°C and 13.9 MPa (2016 psi) to give acryUc acid. Safety problems caused by handling of acetylene are alleviated by the use of tetrahydrofuran as an inert solvent. In this process, the catalyst is a mixture of nickel bromide with a cupric bromide promotor. The hquid reactor effluent is degassed and extracted. The acryUc acid is obtained by distillation of the extract and subsequendy esterified to the desked acryhc ester. The BASF process gives acryhc acid, whereas the Rohm and Haas process provides the esters dkecdy. 

Chemical Designations - Synonym Cupric Bromide, Anhydrous Chemical Formula CuBrj. Observable Characteristics - Physical State (as normally shipped) Solid Color Black Odor None. Physical and Chemical Properties - Physical State at 15 and 1 atm. Solid Molecular Weight 223.35 Boiling Point at 1 atm. Not pertinent (decomposes) Freezing Point 928, 498, 771 Critical Tenqterature Not pertinent Critical Pressure Not pertinent Specific Gravity 4.77 at 20°C (solid) Veqjor (Gas) Density NotpeTtmc at RatioofSpecificHeatsqfVapor(Gas) Not pertinent Z/t/ent Hec/ of Vaporization Not pertinent Heat of Combustion Not pertinent Heat of Decomposition Not pertinent. 

Direct halogenation at C-21 of a A -20-ketopregnane with the common reagents e.g., bromine) is ordinarily not possible. However, by the use of cupric bromide as halogenating agent, a modest yield of the 21-bromo compound can be obtained ... 

Since the sequence includes formation and removal of the dioxolane group, the overall yield is not significantly higher than with the direct cupric bromide halogenation. 

Cholestane-3/3,5a-diol 3-acetate, 397 Cholestane-4a,5a-diol 4-tosylate, 398 Cholestane-5a,6a-diol 6-tosylate,394 5a-Cholestan-2-one, 57, 88, 427 10(5 4 H)ijAeo-Cholestan-5-one, 398 10(5 6)ij ieo-Cholestan-5-one, 392, 394 5a-Cholestan-3-one cyanohydrin, 359 5a-Cholestan-3-one cyanohydrin acetate, 360 5a-Cholestan-2a,3a-oxide, 42 5a-Cholestan-2/3,3/3-thiirane, 43 Cholest-5-ene-3, 19-diol, 268 Cholest-5-ene-3, 25-diol, 71 5(10->l/3H)flfc eo-cholest- 10(19)-ene-3/8,5a-diol 3-acetate, 397, 398 Cholest-4-ene-3,6-dione, 105 Cholest-4-en-3-one, 318 Chromium trioxide, 147, 150 5a-Conanine-3/3-ol-ll-one 3-acetate, 259 Cupric bromide, 210, 211 Cuprous chloride-catalyzed conjugate addition, 76, 80... 

Kupfer-bromid, n. copper bromide, specif, cupric bromide, copper(II) bromide, -bro-mtir, n. cuprous bromide, copper(I) bromide, -chlorid, n. copper chloride, specif, cupric chloride, copper(II) chloride, -chloriir, n. cuprous chloride, copper(I) chloride, -cyamd, Ti. copper cyanide, specif, cupric cyanide, copper(II) cyanide, -cyaniir, n. cuprous cyanide, copper(I) cyanide, -dom, m. slag from liquated copper, -draht, m. copper wire, -drahtnetz, n. copper gauze, -drehspane,... 

A mixture consisting of 22.7 g potassium o-bromobenzoate, 16.6 g 2,6-dichloro-3-methvlani-line, 12 ml N-ethylmorpholine, 60 ml diethylene glycol dimethyl ether, and 1.0 g anhydrous cupric bromide is heated in a nitrogen atmosphere at 145 C to 155°C for 2 hours. The reaction mixture is diluted with 60 ml diethylene glycol dimethyl ether and acidified with 25 ml concentrated hydrochloric acid. The acidic mixture is diluted with 100 ml of water and the liquid phase decanted from the insoluble oil. The insoluble oil is stirred with methanol and the crystalline N-(2,6-dichloro-3-methylphenyl)anthranilic acid which separates is collected and washed with methanol. The product, after recrystallization from acetone-water mixture melts at 248 C to 250°C. 

In the dectrolysis of aqueous cupric bromide, CuBr2, 0.500 gram of copper is deposited at one dectrode. How many grams of bromine are formed at the other electrode Write the anode and cathode half-reactions. 

It is thought that the chlorination proceeds through a ir-com-plex between cupric chloride and anthracene, and that this complex then undergoes homolytic dissociation. Hence aromatic rings subject to attack by chlorine atoms can be chlorinated in this way. Thus one can convert pyrene to 1-chloropyrene (90% yield), but phenanthrene is not chlorinated. Analogous procedures using cupric bromide lead to 9-bromoanthracene (99% yield) and 1-bromopyrene (94% yield).7... 

The methanolic cupric bromide oxidation of propargyl alcohol to trans-BrCH-CBrCH20H (30%) and Br2C=CBrCH20H (18%) and, under other reaction conditions, Br2C-CBr-CH20H (93 %) follows simple second-order kinetics with a rate coefficient of 1.5 x 10 l.mole . sec at 64 °C. A mechanism of ligand-transfer in a 7t-complex is proposed. ... 

Cupric bromide CuBr, 21 35 77gd45-9 TWAlUSA) 1 aitJny... 

Another preparatively useful procedure for monohalogenation of ketones involves reaction with cupric chloride or cupric bromide.121... 

In 2011, Hartwig and coworkers reported the total synthesis of taiwaniaquinol B (55, Scheme 11.9), a member of a family of diterpenoids that are derived from the abietane skeleton [36]. A key aspect of the Hartwig synthesis of taiwaniaquinol B was the use of the iridium-catalyzed borylation reaction to accomplish the C(5) functionalization of resorcinol derivative 53. This regioselectivity for the overall bromination is complementary to that which would be obtained using a standard electrophilic aromatic substitution (EAS) reaction. In the transformation of 53 to 54, a sterically controlled borylation was first accomplished, which was then followed by treatment of the boronic ester intermediate with cupric bromide to... 

This is an improved version of a previously given synthesis (LAC 630,71(1960)). The ethanol used is distilled from Ca ethoxide dimethoxyethane from potassium. Cupric bromide is produced from cupric oxide and 5% excess of HBr, plus sufficient bromine to remove the milkiness on addition of a drop of the mixture to water concentrate and dry, evaporate in vacuum over KOH flakes. 

Cuprammonium rayon, 11 263—265 Cuprate oxides, 23 838-839 Cuprate superconductors, 23 837 Cupric bromide, physical properties of,... 

Copper-catalyzed monoaddition of hydrogen cyanide to conjugated alkenes proceeded very conveniently with 1,3-butadiene, but not with its methyl-substituted derivatives. The most efficient catalytic system consisted of cupric bromide associated to trichloroacetic acid, in acetonitrile at 79 °C. Under these conditions, 1,3-butadiene was converted mainly to (Z )-l-cyano-2-butene, in 68% yield. A few percents of (Z)-l-cyano-2-butene and 3-cyano-1-butene (3% and 4%, respectively) were also observed. Polymerization of the olefinic products was almost absent. The very high regioselectivity in favor of 1,4-addition of hydrogen cyanide contrasted markedly with the very low regioselectivity of acetic acid addition (vide supra). Methyl substituents on 1,3-butadiene decreased significantly the efficiency of the reaction. With isoprene and piperylene, the mononitrile yields were reduced... 

With both building blocks 103 and 109 in hand, the total synthesis of lb was completed as shown in Scheme 17. Coupling of acid 103 and alcohol 109 under Yamaguchi conditions to give ester 110 and subsequent desilylation followed by chemoselective oxidation provided hydroxy acid 111. Lactonization of the 2-thiopyridyl ester derived from 111 in the presence of cupric bromide produced the macrodiolide 112 in 62% yield, which was finally converted to pamamycin-607 (lb) via one-pot azide reduction/double reductive AT-methylation. In summary, 36 steps were necessary to accomplish the synthesis of lb from alcohols 88 and 104, sulfone 91, ketone 93, and iodide rac-97. 

As was pointed out in Part A, Section 7.3, under many conditions halogenation is faster than enolization. When this is true, the position of substitution in unsymmetrical ketones is governed by the relative rates of formation of the isomeric enols. In general, mixtures are formed with unsymmetrical ketones. The presence of a halogen substituent decreases the rate of acid-catalyzed enolization and therefore retards the introduction of a second halogen at the same site. Monohalogenation can therefore usually be carried out satisfactorily. A preparatively useful procedure for monohalogenation of ketones involves reaction with cupric chloride or cupric bromide.81 82 83 84 85 86... 

Helmholz, L. The Crystal Structure of Anhydrous Cupric Bromide. Amer. 

Ammino-cupric Bromides.—Cupric bromide, like euprie chloride, absorbs ammonia gas, forming complex ammino-compounds. The following ammines of cupric bromide have been described Hexammino-cupric bromide, [Cu(NH3)6]Br2 pentammino-cupric bromide, [Cu(NH3)5]Br2 diammino-cupric bromide, [Cu(NTI3)2]Br2 and decammino-tricupric bromide, [Cu3(NH3)10]Br8. 

Hexammino-cupric Bromide, [Cu(NH3)G]Br2, is formed when dry, finely divided cupric bromide is exposed to ammonia gas at ordinary temperature. It is stable up to 20° C., but above that temperature... 

Diammino-eupric Bromide, [Cu(NII3)2]Br2.—On exposure to air hexammino-cupric bromide and other alleged higher ammines lose ammonia and are transformed into the more stable diammino-bromide. 

Diammino-eupric bromide is very dark in colour it is soluble in a concentrated aqueous solution of ammonium bromide, from which it may be crystallised water alone decomposes the ammine completely. It is capable of absorbing ammonia gas, forming the higher ammino-derivatives, and it may be heated to 200° C. without decomposition. At 260° C. it begins to decompose, and above that temperature it loses ammonia, leaving a residue of cupric bromide and some cupric oxide.2... 

Cumyl Hydroperoxide Cupric Acetate Monohydrate Cupric Arsenite Cupric Bromide, Anhydrous Cupric Chloride Dihydrate Cupric Fluoborate Solution Cupric Green Cupricin... 

Metalated ferrocenes have served as valuable intermediates for the synthesis of a number of other derivatives. Treatment of lithiated ferrocenes with tributyl borate followed by hydrolysis leads to ferroceneboronic acid (XXXIII) as well as the diboronic acid (73). Ferroceneboronic acid, like benzeneboronic acid, is readily cleaved by cupric bromide or cupric chloride to form the corresponding halo derivatives (XXXIV). Ferrocene-l,l -diboronic acid reacts in the same manner, and either one or two carbon-boron bonds can be cleaved. Further reactions of this type have led to a variety of mixed dihaloferrocenes (73, 75). 

Phenyltrimethylammonium bromide perbromide (PhMe3N Br3) was introduced as a reagent for the bromination of cyclic ketals81 (see section IV) but it has also been utilized for the selective bromination of ketones containing double bonds.82 The same claim has been made for cupric bromide as a brominating agent 83 yields are not good, however, and in methanol, the solvent usually employed, the formation of methoxy-substituted products is a common side reaction (cf. ref. 84, 85). 

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