Cupric bromide oxide

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. ... 

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... 

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,... 

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. 

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... 

They also tried soln. of cupric chloride in acetic acid, formic acid, acetone, and methyl and ethyl alcohols. With 0-37, 0-62, and 0-925 litre of soln. with a mol of cupric bromide, 0-515, 0-120, and 0-000 litre of nitric oxide were respectively absorbed. They also tried soln. of cupric bromide in ethyl alcohol. E. Peligot found that nitric oxide is absorbed by aq. soln. of stannous salts (vide infra) and chromous salts. According to G. Chesneau, a soln. of ckromous chloride absorbs nitric oxide in the ratio CrCl2 NO=3 1, and the blue liquid becomes dark red. When heated, the nitric oxide is not expelled as in the case of ferrous salts, but the liquid becomes greenish-brown, and the nitric oxide is reduced to ammonia or hydroxylamine. The action of nitric oxide on soln. of chromous salts was also studied by V. Kohlschiitter, and J. Sand and O. Burger. 

Cupric bromide, CiiBr., is a black solid obtained by reaction of copper and bromine or by solution of cupric oxide, CuO, in hydro bromic acid. It is interesting that cupric iodide, Culo, does not exist when a solution containing cupric ion is added to an iodide solution there occurs an oxidation-reduction reaction, with precipitation of (uprous iodide, Cul ... 

Ores of copper native copper, cuprite, chalcocite, chalcopyrite, malachite, azurite. Metallurgy of ores containing native copper, oxide and carbonate ores, sulfide ores. Gangue, flux, flotation, roasting of ores, matte, blister copper. Cupric compounds copper sulfate (blue vitriol, bluestone), Bordeaux mixture, cupric chloride, cupric bromide, cupric hydroxide. Test for cupric ion with Fehling s solution. Cuprous compounds cuprous chloride, cuprous bromide, cuprous iodide, cuprous oxide. Covalent-bond structure of cuprous compounds. 

Oxidation [1, 303-308] In a search for a convenient synthesis of ninhydrin, Schipper et a/.35a applied the Kornblum oxidation to 2-bromo-l,3-indanedione O and indeed obtained ninhydrin (2) in 36% yield. The bromo compound (1) was prepared by bromination of 1,3-indanedione with cupric bromide (1, 161). Subsequent-... 

Oxidative decarboxyiation with aromatisation of the angular carboxy dimethoxy compound shown by treatment of a methanolic solution with a solution of methanolic cupric bromide followed by refluxing for 1.5 hours furnished a 76% yield of... 

Cupric bromide phenyllithium Oxidative dimerization via organocopper compounds... 

As was noted by Jones (ref. 12) the success of a metal bromide as a catalyst for alkylaromatic autoxidations depends on the ability of the metal to transfer rapidly and efficiently oxidizing power from various autoxidation intermediates onto bromide ion in a manner which generates Br-. The fact that no free bromine is observable in this system is consistent with rapid reaction of intermediate bromine atoms with the substrate. Inhibition of the reaction by cupric salts can be explained by the rapid removal of Br2 or ArCH2- via one-electron oxidation by Cu (Fig. 10). 

Hydrofluoric acid like water is an associated liquid, and even the gas, as we shall soon see, is associated. It has the power of uniting with fluorides. It also seems to be an ionizing solvent for a soln. of potassium fluoride in liquid hydrogen fluoride is an excellent conductor it also possesses marked solvent powers. According to E. C. Franklin,7 the liquid readily dissolves potassium fluoride, ehloride, and sulphate sodium fluoride, bromide, nitrate, chlorate, and bromate acetamide and urea. The solvent action is not so marked with barium fluoride, cupric chloride, and silver cyanide while calcium and lead fluorides copper sulphate and nitrate ferric chloride, mercuric oxide, and magnesium metal, are virtually insoluble in this menstruum. Glass also is not affected by the liquid if moisture be absent. The liquid scarcely acts on most of the metals or non-metals at ordinary temp., though it does act on the alkali metals at ordinary temp., much the same as does water, with the simultaneous production of flame. 

Compound 287, which is obtained from 7V-carbethoxymethyl-2-methyl-pyridinium bromide and diethyl mesoxalate, undergoes base-catalyzed cyclization to betaine 288 which is readily converted to the quinolizinium-3-olate 286 (R = COjEt, = COjH). Decarboxylation of this compound (286 R = COjEt, R = CO2H) by cupric oxide and quinoline at 180-190 C gives the unsubstituted betaine (286 R = R = Quinolizinium-3-... 

Hydrolysis of chlorobenzene and the influence of silica gel catalysts on this reaction have been studied by Freidlin and co-workers (109). Pure silica gel gave up to 45% phenol from chlorobenzene at 600°C. When the silica gel was promoted with 2% cupric chloride, up to 75% phenol was obtained (381). A number of other salts were tested by Freidlin and co-workers as promoters, but they exerted an adverse effect on the activity or selectivity of the catalyst. With 0.2% cupric chloride and 6% metallic copper, the activity of silica-gel was doubled (389). At 500° under the above conditions, the halides were hydrolyzed at rates decreasing in the following order chloride, bromide, iodide, fluoride (110). The specific activation of aryl halides by cupric chloride was demonstrated by conversion of chlorobenzene to benzene and of naphthyl chloride to naphthalene when this catalyst was supported on oxides of titanium or tin (111). The silica promoted with cupric chloride was also found to be suitable for hydrolysis of chlorophenols and dichlorobenzenes however, side reactions were too prominent in these cases (112). 

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