Ruthenium tetroxide complexes

The conversion of primary alcohols and aldehydes into carboxylic acids is generally possible with all strong oxidants. Silver(II) oxide in THF/water is particularly useful as a neutral oxidant (E.J. Corey, 1968 A). The direct conversion of primary alcohols into carboxylic esters is achieved with MnOj in the presence of hydrogen cyanide and alcohols (E.J. Corey, 1968 A,D). The remarkably smooth oxidation of ethers to esters by ruthenium tetroxide has been employed quite often (D.G. Lee, 1973). Dibutyl ether affords butyl butanoate, and tetra-hydrofuran yields butyrolactone almost quantitatively. More complex educts also give acceptable yields (M.E. Wolff, 1963). 

Ethers in which at least one group is primary alkyl can be oxidized to the corresponding carboxylic esters in high yields with ruthenium tetroxide. Molecular oxygen with a binuclear copper (II) complex " or PdCVCuCVCO " also converts ethers to esters. Cyclic ethers give lactones. " The reaction, a special case of 19-14,... 

Aliphatic alcohols can be oxidized to ketones, aldehydes, or carboxylic acids using oxoruthenium(IV)complexes as redox catalyst or clectrogenerated ruthenium tetroxide In the latter case, a double mediator system is used in which an electrochemically generated active chlorine species (Cl or CP ) oxidizes RuO to RUO4 (Eq. (29)). 

Treatment of 2-aryIfurans with ruthenium tetroxide leads to radical cations which form purple solutions of a charge transfer complex with the reagent. Oxidation of 2-arylfurans in a two-phase system with ruthenium tetroxide and aqueous hypochlorite yields products whose formation can be interpreted in terms of the radical cation intermediate (76CC890). 

A cobalt(II)-catalyzed oxidative cyclization converted a secondary alcohol to the trans-2,5-disubstituted tetrahydrofuran <03JA14702>. Oxidants such as vanadium(V) complex <03EJO2388>, ruthenium tetroxide <03TL5499> and osmium tetroxide <03AG(E)948> were all employed to convert either homoallyl alcohol or polyenes to molecules that contain... 

Diarylacetylenes are converted in 55-90% yields into a-diketones by refluxing for 2-7 h with thallium trinitrate in glyme solutions containing perchloric acid [413. Other oxidants capable of achieving the same oxidation are ozone [84], selenium dioxide [509], zinc dichromate [660], molybdenum peroxo complex with HMPA [534], potassium permanganate in buffered solutions [848, 856, 864,1117], zinc permanganate [898], osmium tetroxide with potassium chlorate [717], ruthenium tetroxide and sodium hypochlorite or periodate [938], dimethyl sulfoxide and iV-bromosuccin-imide [997], and iodosobenzene in the presence of a ruthenium catalyst [787] (equation 143). 

Ruthenium tetroxide was shown to oxidize PCBs in water [20], Water-soluble ruthenium complexes, such as [Ru(H20)2(DMS0)4]2+, are effective catalysts for the KHSO5 deep oxidation of a number of chloroaliphatics, of a-chlorinated al-kenes, polychlorobenzenes, and polychlorophenols. When the reactions are carried out in water in the presence of surfactant agents, degradation of the substrates is definitely faster. Aromatic substrates are mainly converted into HC1 and C02, polychlorophenols being more sensitive to oxidation than substituted benzenes [21]. Replacement of the DMSO- solvated ruthenium by RuPcS results in a definite improvement of the reaction course with hydrogen peroxide, since dismutation of... 

Analysis of phenols in complex mixtures and in industrial wastes using UV detection and monitoring of trace phenols in aqueous environmental samples with the use of fluorimetric detectors have been achieved by HPLC. Chlorophenols, which can be formed during the disinfection of industrial waste by chlorination, can be analyzed as quinones after oxidation by ruthenium tetroxide. 

Amino acids. Oxidation of aliphatic primary amines with ruthenium tetroxide leads to complex products. However, oxidation of aralkylamines at pH 3.0 with periodate (12 eq.) and RuCls 3H2O (0.02 eq.) converts the aromatic ring into a carboxyl group to give amino acids. Cleavage is facilitated by a 4-methoxy or hydroxy substituent in the ring. ... 

The phase-transfer-assisted permanganate oxidation of alkynes and alkenes has been reviewed. Terminal and internal alkynes are oxidized to 1,2-dicarbonyl compounds by the combined action of diphenyl disulphide, ammonium peroxidisulphate and water or by sodium periodate in the presence of ruthenium dioxide (equation 34). Other reagents for the conversion of acetylenes into 1,2-dicarbonyl compounds are hydrogen peroxide in the presence of (2,6-dicarboxylatopyridine)iron(II), the complex oxo(A, A -ethylenebissalicylideneiminato)chromium(V) trifluoromethanesulphonate (216)and ruthenium tetroxide as a mediator in electrooxidation. l-Acetoxyalkan-2-ones 217 are obtained by the oxidation of terminal acetylenes with sodium perborate and mercury(II) acetate in acetic acid ". Terminal alkynes give a-ketoaldehydes 218 on treatment with dilute hydrogen peroxide, combined with mercury(II) acetate and sodium molybdate or sodium tungstate under phase-transfer conditions. ... 

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