Copper I cyanide

Addition of aqueous cyanide ion to a copper(II) solution gives a brown precipitate of copper(II) cyanide, soluble in excess cyanide to give the tetracyanocuprate(II) complex [Cu(CN)4] . However, copper(II) cyanide rapidly decomposes at room temperature, to give copper(I) cyanide and cyanogen(CN)2 (cf. the similar decomposition of copper(II) iodide, below) excess cyanide then gives the tetracyanocuprate(I) [Cu(CN)4] . 

In the first method a secondary acetylenic bromide is warmed in THF with an equivalent amount of copper(I) cyanide. We found that a small amount of anhydrous lithium bromide is necessary to effect solubilization of the copper cyanide. Primary acetylenic bromides, RCECCH Br, under these conditions afford mainly the acetylenic nitriles, RCsCCHjCsN (see Chapter VIII). The aqueous procedure for the allenic nitriles is more attractive, in our opinion, because only a catalytic amount of copper cyanide is required the reaction of the acetylenic bromide with the KClV.CuCN complex is faster than the reaction with KCN. Excellent yields of allenic nitriles can be obtained if the potassium cyanide is added at a moderate rate during the reaction. Excess of KCN has to be avoided, as it causes resinifi-cation of the allenic nitrile. In the case of propargyl bromide 1,1-substitution may also occur, but the propargyl cyanide immediately isomerizes under the influence of the potassium cyanide. 

In the flask were placed 0.40 mol of dry, powdered copper(I) cyanide, 9 g of anhydrous lithium bromide (note 1), 50 ml of dry THF and 0.30 mol of l-bromo-2--heptyne (prepared from the corresponding alcohol and PBrs in diethyl ether, see VIII-2, Exp. 10). The mixture was heated until an exothermic reaction started, which occurred at about 80°C. The solid dissolved gradually. The mixture was kept... 

In the flask were placed a solution of 7 g of anhydrous LiBr in 50 ml of dry THF, 0.40 mol of the allenic bromide (see Chapter VI, Exp. 31) and 0.50 mol of finely powdered copper(I) cyanide. The mixture was swirled by hand and the temperature rose in about 15 min to 60°C. It was kept between 55 and 60°C by occasional cooling in a water-bath. When the exothermic reaction had subsided, the flask was warmed for an additional 30 min at 55-60°C and the brown solution was then poured into a vigorously stirred solution of 30 g of NaCN and 100 g of NH,C1 in 300 ml of water, to which 150 ml of diethyl ether had been added. During this operation the temperature was kept below 20 c. The reaction flask was subsequently rinsed with the NaCN solution. After separation of the layers the aqueous layer was extracted with ether. The extracts were dried over magnesium sulfate and then concentrated... 

Reactions that employ copper(I) salts as reagents for replacement of nitrogen m diazo mum salts are called Sandmeyer reactions The Sandmeyer reaction using copper(I) cyanide is a good method for the preparation of aromatic nitriles... 

Bromomethyl-5-methylthiophene gives normal displacement products with amines but it is isomerized on attempted reaction with copper(I) cyanide (Scheme 59) 48MI30200. Whereas 2-hydroxymethylthiophene reacts normally with hydrogen halides to give 2-halomethylthiophenes, reaction of 2-hydroxymethylfuran (2-furfuryl alcohol) with hydrochloric acid results in formation of laevulinic acid (151). 2-Furfuryl alcohol derivatives are... 

Cupro-. cuprous, copper(I), cupro-. -chlorid, n. cuprous chloride, copper(I) chloride, -cy-aniir, n. cuprous cyanide, copper(I) cyanide cuprocyanide, cyanocuprate(I). -jodid, n. cuprous iodide, copper(I) iodide, -mangan, n. cupromanganese. -oxyd, n. cuprous oxide, copper(I) oxide, -salz, n. cuprous salt, cop-per(I) salt, -suifocyantir, n. cuprous thiocyanate, copper (I) thiocyanate, -verbin-dUDg, /. cuprous compound, copper(I) compound. 

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,... 

The bromo substituent in 10-bromodibenz[/>,/]oxepin can be replaced by nucleophiles. With copper(I) cyanide in the presence of pyridine, dibenz[fr,/]oxepin-10-carbonitrile (3) is obtained.161 The substitution of bromine by various TV-substituted piperazines to give dibenz[/>,/]oxepins 4 has been accomplished using potassium cm-butoxide.197 This latter reaction probably proceeds via an intermediate with a C-C triple bond.160... 

Trithiadiazepine 4 is readily thalliated by thallium(III) trifluoroacetate the product 19 reacts in situ with potassium iodide, copper(I) cyanide, and methanol/carbon monoxide300 to give 20a-c, respectively.33 ... 

PcH2 was obtained for the first time in 1907 as a byproduct during the preparation of 2-cyanobenzamide.50 However, this discovery initiated no interest at that time. In 1927, PcCu was prepared in 23% yield by heating 1,2-dibromobenzene with copper(I) cyanide in pyridine.51 The term phthalocyanine was first used by Linstead in 1933.52 From 1929 to 1939, Linstead et al. elucidated the structure of phthalocyanines and developed improved synthetic methods for several metal phthalocyanines.52 - 61... 

A second reaction which is very often used for the preparation of phthalonitriles, although the yields are usually not reproducible, is the Rosenmund-von Braun reaction (see Houben-Weyl, Vol. E5, p 1460).106 107 Herein, a benzene derivative with a 1,2-dibromidc or 1,2-dich-loride unit is treated with copper(I) cyanide in dimethylformamidc or pyridine. During this reaction the formation of the respective copper phthalocyanine often occurs. This can be used as an easy procedure for the exclusive synthesis of copper phthalocyanines (see Section 2.1.1.7.),1 os-109 but can also lead to problems if the phthalonitrile is required as the product. For example, if l,2-dibromo-4-trifluoromethyl-benzene is subjected to a Rosenmund-von Braun reaction no 4-trifluoromethylphthalonitrile but only copper tetra(tri-fluoromethyljphthalocyanine is isolated.110... 

Due to its commercial importance, the synthesis of copper phthalocyanine (PcCu) is the best investigated of all the phthalocyanines. Copper phthalocyanine is prepared from phthalonitrile and copper(I) chloride without solvent137 and also in a melt of urea.229,277 Additionally, the insertion of copper into metal-free phthalocyanine in butan-l-ol and pentan-l-ol is possible. The copper salts used in this case are copper(I) chloride112 and copper(II) acetate.290 Starting from copper(II) acetate, copper phthalocyanine can also be prepared in ethylene glycol.127 As mentioned above, copper phthalocyanine often occurs as a byproduct of the Rosenmund-von Braun reaction. To increase the yield of the phthalocyanine the solvent dimethylformamide can be substituted by quinoline. Due to the higher boiling point of quinoline, the copper phthalocyanine is the main product of the reaction of copper(I) cyanide and 1,2-dibromoben-zene.130... 

In copper-catalyzed Grignard reactions of allylic carboxylates, high y regioselectivity is observed when copper(I) cyanide is used as catalyst16. 

A solution of trimethylsilyl lithium (10 mmol) in HMPA (CAUTION— CANCER SUSPECT AGENT) (5 ml) and ether (10 ml, from the MeLi) prepared as above was cooled to 0°C and diluted with THF (20 ml). Copper(i) cyanide (5 mmol) was added in one portion, and the resulting black mixture was stirred at 0°C for 20min. 

Conjugate addition, 34-5, 51-2,53, 132, 133 Conjugate hydroxymethylation, 59-60 Copper(n) bromide, 54 Copper([) chloride, 120 Copper(n) chloride, 120 Copper(i) cyanide, 7,52, 53 Copper(i) iodide, 54 Corey s internal quench, 104 Cyanohydrin trimethylsilyl ether, 137 Cycloaddition. 34,112 Cydobutane-l,2-dione, 135 Cyclohept-2-dione, 135 Cyclohex-2-enone, 52,123 Cyclohcxa-1,3-diene, 26 Cyclohexane carboxaldehyde, 22-3,69 73,78... 

To a stirred slurry of copper(i) cyanide (110 mmol) in THF (100 ml), cooled to 0 °C, was added a solution of dimethylphenylsilyl lithium (220 mmol, 1.3 m in THF), and the mixture was stirred at 0°C for a further 30min. After cooling to —78°C, a solution of methyl cinnamate (100mmol) in THF (50 ml) was added, and stirring was continued at —78°Cfor6h. At this time, iodomethane (300 mmol) (CAUTION—CANCER SUSPECT AGENT) was added, and the mixture allowed to warm to ambient temperature with... 

There has been a plethora of recent hterature regarding the synthetic manipulations of the 2(lH)-pyrazinone skeleton. Even though the addition-elimination reactions at the C-3 position to decorate the pyrazinone scaffold are well documented [24], the versatihty of such approaches can be found somewhat limited. Selective attack of nucleophiles on the chloroimine group of the pyrazinone system can generate 3-alkoxy- and 3-amino-pyrazinones (Scheme 9) [27,28]. The 3-CN group was introduced via a Rosemund-von Braun reaction with copper(I)cyanide under harsh conditions (heating in NMP at 150 °C) [27] (Scheme 9). 

The cyanide ion is an ambident nucleophile and isocyanides may be side products. If the preparation of isocyanides is desired, they can be made the main products by the use of silver or copper(I) cyanide (p. 459). Vinylic bromides can be converted to vinylic cyanides with CuCN, with KCN, a crown ether, and a... 

Arylthallium bis(trifluoroacetates) (see 12-21) can be converted to aryl nitriles by treatment with copper(I) cyanide in acetonitrile. Another procedure uses excess aqueous KCN followed by photolysis of the resulting complex ion ArTl(CN)3 in the presence of excess KCN. Alternatively, arylthallium acetates react with Cu(CN)2 or CuCN to give aryl nitriles. Yields from this procedure are variable, ranging from almost nothing to 90 or 100%. 

C10H12O2 536-66-3) see Nateglinide cuprous cyanide see under copper(I) cyanide cyanamide... 

There has been a great deal of study concerning the effect of solvents and other reaction conditions on the stability and reactivity of organocuprate species.8 These studies have found, for example, that (CH3)2S-CuBr, a readily prepared and purified complex of CuBr, is an especially reliable source of Cu(I) for cuprate preparation.9 Copper(I) cyanide and iodide are also generally effective and, in some cases, preferable.10... 

After preparation from interaction of 3-bromopropyne with copper(I) cyanide and filtration from copper salts, an explosion occurred dining distillation of the evaporated filtrate at 45-60°C/66 mbar. This was attributed to explosion of some dissolved copper acetylide(s). After refiltration the product was again distilled at 45-48°C/53 mbar without incident, and it appeared to be stable, unlike true haloalkynes. However it is undoubtedly an endothemic compound with its two triple bonds. 

When the published method [1] for preparing the 4-isomer is used to prepare 2-nitrobenzonitrile, a moderate explosion often occurs towards the end of the reaction period. (This may be owing to formation of nitrogen trichloride as a byproduct.) Using an alternative procedure, involving heating 2-chloronitrobenzene with copper(I) cyanide in pyridine for 7 h at 160°C, explosions occurred towards the end of the heating period in about 20% of the preparations [2],... 

See 4-Chloro-3-nitrotoluene Copper(I) cyanide, Pyridine See other cyano compounds, nitroaryl compounds... 

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