Iodine-copper® acetate

Catalysts. Iodine and its compounds ate very active catalysts for many reactions (133). The principal use is in the production of synthetic mbber via Ziegler-Natta catalysts systems. Also, iodine and certain iodides, eg, titanium tetraiodide [7720-83-4], are employed for producing stereospecific polymers, such as polybutadiene mbber (134) about 75% of the iodine consumed in catalysts is assumed to be used for polybutadiene and polyisoprene polymeri2a tion (66) (see RUBBER CHEMICALS). Hydrogen iodide is used as a catalyst in the manufacture of acetic acid from methanol (66). A 99% yield as acetic acid has been reported. In the heat stabiH2ation of nylon suitable for tire cordage, iodine is used in a system involving copper acetate or borate, and potassium iodide (66) (see Tire cords). 

Treatment of 3,7,7-trimethylbicyclo[4.1.0]heptane (A3-carene) with iodine and copper acetate in methanol gave 3-iodo-4-methoxy-4,7,7-trimethylbicyclo[4.1.0] heptane. A 50 g sample exploded violently after standing at ambient temperature in a closed container for 10 days. This and the corresponding iodoacetoxy... 

Iodine-copper(II) acetate, 267 Iodine-mercury(II) oxide, 267-268 Iodine monochloride, 268-269 Iodine-silver carboxylates, 268 Iodine-silver nitrate, 268 lodoamination, 265-266 Iodocarbamation, 264-265 Iodocarbonates, 263 2 Iodoestradiol, 267 2-Iodoestrone, 267 Iodoiactonization, 263-264 C,-Iodomethylcephalosporins, 273 Iodonium di-svm-collidine perchlorate, 269 19-Iodononadecanic acid, 488 Iodophenylbis(triphenylphosphine)palladium, 269... 

Estradiol was heated at 55C with copper(II) acetate monohydrate and iodine in acetic acid for 2h. to give 2-iodoestradiol. 

We have been investigating an iodination method using iodine-copper(II) acetate and iodine-ammonium cerium(lV) nitrate (CAN) to synthesize iodoletones. These iodoketones are more active than chloro- and bromoketones, and it was found that they are unstable and sensitive to Hght. From the viewpoint of green chemistry, we have tried to transform these iodo compounds into useful products by photochemical methods. 

The majority of preparative methods which have been used for obtaining cyclopropane derivatives involve carbene addition to an olefmic bond, if acetylenes are used in the reaction, cyclopropenes are obtained. Heteroatom-substituted or vinyl cydopropanes come from alkenyl bromides or enol acetates (A. de Meijere, 1979 E. J. Corey, 1975 B E. Wenkert, 1970 A). The carbenes needed for cyclopropane syntheses can be obtained in situ by a-elimination of hydrogen halides with strong bases (R. Kdstcr, 1971 E.J. Corey, 1975 B), by copper catalyzed decomposition of diazo compounds (E. Wenkert, 1970 A S.D. Burke, 1979 N.J. Turro, 1966), or by reductive elimination of iodine from gem-diiodides (J. Nishimura, 1969 D. Wen-disch, 1971 J.M. Denis, 1972 H.E. Simmons, 1973 C. Girard, 1974),... 

Stereoselective cis-dihydroxylation of the more hindered side of cycloalkenes is achieved with silver(I) or copper(II) acetates and iodine in wet acetic acid (Woodward gly-colization J.B. Siddall, 1966 L. Mangoni, 1973 R. Criegee, 1979) or with thallium(III) acetate via organothallium intermediates (E. Glotter, 1976). In these reactions the intermediate dioxolenium cation is supposed to be opened hydrolytically, not by Sn2 reaction. 

Preparation. Thiophosgene forms from the reaction of carbon tetrachloride with hydrogen sulfide, sulfur, or various sulfides at elevated temperatures. Of more preparative value is the reduction of trichi oromethanesulfenyl chloride [594-42-3] by various reducing agents, eg, tin and hydrochloric acid, staimous chloride, iron and acetic acid, phosphoms, copper, sulfur dioxide with iodine catalyst, or hydrogen sulfide over charcoal or sihca gel catalyst (42,43). 

Phenyl isothiocyanate has been prepared from thiocarbanilide by the action of phosphorus pentoxide, hydrochloric acid, iodine, phosphoric acid, acetic anhydride, and nitrous acid. It has also been prepared from ammonium phenyl dithiocarbamate by the action of ethyl chlorocarbonate, copper sulfate lead carbonate, lead nitrate, ferrous sulfate,and zinc sulfate. ... 

A cursory inspection of key intermediate 8 (see Scheme 1) reveals that it possesses both vicinal and remote stereochemical relationships. To cope with the stereochemical challenge posed by this intermediate and to enhance overall efficiency, a convergent approach featuring the union of optically active intermediates 18 and 19 was adopted. Scheme 5a illustrates the synthesis of intermediate 18. Thus, oxidative cleavage of the trisubstituted olefin of (/ )-citronellic acid benzyl ester (28) with ozone, followed by oxidative workup with Jones reagent, affords a carboxylic acid which can be oxidatively decarboxylated to 29 with lead tetraacetate and copper(n) acetate. Saponification of the benzyl ester in 29 with potassium hydroxide provides an unsaturated carboxylic acid which undergoes smooth conversion to trans iodolactone 30 on treatment with iodine in acetonitrile at -15 °C (89% yield from 29).24 The diastereoselectivity of the thermodynamically controlled iodolacto-nization reaction is approximately 20 1 in favor of the more stable trans iodolactone 30. 

Alternative procedure. The following method utilises a trace of copper sulphate as a catalyst to increase the speed of the reaction in consequence, a weaker acid (acetic acid) may be employed and the extent of atmospheric oxidation of hydriodic acid reduced. Place 25.0 mL of 0.017M potassium dichromate in a 250 mL conical flask, add 5.0 mL of glacial acetic acid, 5 mL of 0.001M copper sulphate, and wash the sides of the flask with distilled water. Add 30 mL of 10 per cent potassium iodide solution, and titrate the iodine as liberated with the approximately 0.1M thiosulphate solution, introducing a little starch indicator towards the end. The titration may be completed in 3-4 minutes after the addition of the potassium iodide solution. Subtract 0.05 mL to allow for the iodine liberated by the copper sulphate catalyst. 

The reaction is a sensitive one, but is subject to a number of interferences. The solution must be free from large amounts of lead, thallium (I), copper, tin, arsenic, antimony, gold, silver, platinum, and palladium, and from elements in sufficient quantity to colour the solution, e.g. nickel. Metals giving insoluble iodides must be absent, or present in amounts not yielding a precipitate. Substances which liberate iodine from potassium iodide interfere, for example iron(III) the latter should be reduced with sulphurous acid and the excess of gas boiled off, or by a 30 per cent solution of hypophosphorous acid. Chloride ion reduces the intensity of the bismuth colour. Separation of bismuth from copper can be effected by extraction of the bismuth as dithizonate by treatment in ammoniacal potassium cyanide solution with a 0.1 per cent solution of dithizone in chloroform if lead is present, shaking of the chloroform solution of lead and bismuth dithizonates with a buffer solution of pH 3.4 results in the lead alone passing into the aqueous phase. The bismuth complex is soluble in a pentan-l-ol-ethyl acetate mixture, and this fact can be utilised for the determination in the presence of coloured ions, such as nickel, cobalt, chromium, and uranium. 

SO2CI2) or with I2 and silver acetate. Enol acetates have been regioselec-tively iodinated with I2 and either thallium(I) acetateor copper(II) acetate. ot,P-... 

Free-radical acyloxylation of aromatic substrates has been accomplished with a number of reagents including copper(II) acetate,benzoyl peroxide-iodine, silver(II) complexes, and cobalt(III) trifluoroacetate. ... 

Acyloins were converted to mixtures of stereoisomeric vicinal diols by catalytic hydrogenation over copper chromite [972]. More frequently they were reduced to ketones by zinc (yield 77%) [913, 914], by zinc amalgam (yields 50-60%) [975], by tin (yields 86-92%) [173], or by hydriodic acid by refluxing with 47% hydriodic acid in glacial acetic acid (yields 70-90%) [916], or by treatment with red phosphorus and iodine in carbon disulfide at room temperature (yields 80-90%) [917] Procedure 41, p. 215). Since acyloins are readily accessible by reductive condensation of esters (p. 152) the above reductions provide a very good route to ketones and the best route to macro-cyclic ketones [973]. 

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