Ruthenium chloride, tris oxidation

A number of derivatives of ruthenium(II) have the potential to oxidize a primary alcohol in the presence of a secondary alcohol the original report of Sharpless et al has been followed by a number of modifications. The ruthenium complex can be used as a catalyst in conjunction with a cooxidant, which in the original work was A -methylmorpholine A -oxide. In general benzylic and allylic alcohols react more readily than their saturated counterparts, and primary alcohols react more readily than secondary alcohols. Alkenes can interfere with this oxidation, probably by binding to the metal and inhibiting the catalytic process. The stoichiometric use of tris(triphenylphosphine)ruthenium(II) chloride will oxidize a primary/secondary diol to the corresponding hydroxy aldehyde in excellent yield (equation 13). ... 

The use of electricity in reactions is clean and, at least in some cases, can produce no waste. Toxic heavy metal ions need not be involved in the reaction. Hazardous or expensive reagents, if needed, can be generated in situ where contact with them will not occur. The actual oxidant is used in catalytic amounts, with its reduced form being reoxidized continuously by the electricity. In this way, 1 mol% of ruthenium(III) chloride can be used in aqueous sodium chloride to oxidize benzyl alcohol to benzaldehyde at 25°C in 80% yield. The benzaldehyde can, in turn, be oxidized to benzoic acid by the same system in 90% yield.289 The actual oxidant is ruthenium tetroxide. Naphthalene can be oxidized to naphthoquinone with 98% selectivity using a small amount of cerium salt in aqueous methanesulfonic acid when the cerium(III) that forms is reoxidized to cerium(IV) electrically.290 Substituted aromatic compounds can be oxidized to the corresponding phenols electrically with a platinum electrode in trifluoroacetic acid, tri-ethylamine, and methylene chloride.291 With ethyl benzoate, the product is a mixture of 44 34 22 o/m/fhhy-... 

Chloro-2-(3-methyl-4H-1,2,4-triazol-4-yDbenzophenone (Oxidation of 7solution prepared by adding sodium periodate (2 g) to a stirred suspension of ruthenium dioxide (200 mg) in water (35 ml). The mixture became dark. Additional sodium periodate 18 g) was added during the next 15 minutes. The ice-bath was removed and the mixture was stirred for 45 minutes. Additional sodium periodate (4 g) was added and the mixture was stirred at ambient temperature for 18 hours and filtered. The solid was washed with acetone and the combined filtrate was concentrated in vacuo. The residue was suspended in water and extracted with methylene chloride. The extract was dried over anhydrous potassium carbonate and concentrated. The residue was chromatographed on silica... 

The tris(ethylenediamine)ruthenium(III) species is obtained by oxidation of [Ru(en)3]2+ with, for example, iodine4 or bromine.6 The oxidizing agent and conditions employed must be chosen carefully to avoid further oxidation of the ethylenediamine ligand to coordinated diimine.7 In the present procedure solid silver anthranilate is used to oxidize [Ru(en)3] [ZnCl4], and [Ru(en)3] Cl3 is isolated. In this heterogeneous procedure the desired [Ru(en)3]Cl3 is the only soluble product and can easily be separated from the insoluble silver, silver chloride, and zinc dianthranilate. Other less soluble [Ru(en)3]3+ compounds can be obtained easily from the soluble chloride. 

Anhydrous ruthenium(lll) chloride, RuCL, is made by direct chlorination of the metal at 700°C. Two aliotropic forms result. The trihydrate is made by evaporating an HQ solution of rulheinuiu(III) hydroxide to dryness or reducing ruthenium(VIII) oxide in a HQ solution. The tnhydrate, RuCk 3R>0, is the usual commercial form. Aqueous solutions of the tri-hydrate are a straw color in dilute solution and red-brown in concentrated solution. Ruthenium(lll) chloride in solution apparently forms a variety of aquo- and hydroxy complexes. The analogous bromide. RuBr3, is made by the same solution techniques as the chloride, using HBr instead of HQ. 

There are several methods reported in the literature for transforming vicinal diols into ct-diketones while avoiding the risk of C-C bond cleavage.26 Examples include the standard Swem conditions (dimethyl sulfoxide and oxalyl chloride followed by triethylamine), or the use of DMSO activated by acetic anhydride, pyridine-sulfur trioxide complex, or dicyclohexylcarbodiimide (Mq/J-att oxidation). Diones are also obtained by treatment with benzalacetone as a hydride acceptor in the presence of catalytic amounts of tris(triphenylphosphine)ruthenium dichlonde [(PPh RuCFl.27 Recent developments include the use of w-iodoxyben/.oic acid28 or the oxoammonium salt of 4-acctamidoletramethylpipcridine-1-oxyl and y -toluencNulfonic acid.29... 

A sensor for organic chloride-containing compounds was constructed by immobilization of luminol or tris (2,2 bipyridyl) ruthenium (III) between a PMT and a poly (tetrafluoro) ethylene (PTFE) membrane [15], through which a stream of air was sampled by diffusion. A heated Pt filament incorporated in the gas line leading to the CL cell was used to oxidize the analytes prior to diffusion across the PTFE membrane. Detection limits for CC14, CHC13, and CH2C12 were 1.2-4 ppm. A similar device could also be used for the determination of hydrazine and its monomethyl and dimethyl derivatives or NH3 vapor. The detection limit for hydrazine was only 0.42 ppb [16]. 

It is possible to oxidize sensitive allylic alcohols to aldehydes using catalytic tris(triphenylphos-phine)ruthenium(II) chloride in an oxygen atmosphere, a thiophenyl group survives under these condi-... 

Bis(trimethylsilyl) peroxide, (CH3)3SiOOSi(CH3)3, is prepared from trimethylsilyl chloride, l,4-diaza[2,2,2]bicyclooctane, and Dabco s complex with 2 mol of hydrogen peroxide [127]. It is used alone [228] or in the presence of catalysts such as pyridinium dichromate [236] trimethylsilyl trifluoromethanesulfonate, CF3S03Si(CH3)3 [228, 237] or tris-(triphenylphosphine)ruthenium dichloride, [(C6H5)3P]3RuCl2 [236]. This reagent oxidizes primary alcohols to aldehydes (in preference to the oxidation of secondary alcohols to ketones [236]), ketones to esters or lactones Baeyer-Villiger reaction) [238], and nucleoside phosphites to phosphates [228]. All these oxidations require anhydrous conditions. 

However, oxidation of the 26-diethylaminoethylthio derivative of pristinamycin IIb (94a), or the corresponding sulfinyl analog (97), using ruthenium tetroxide generated in situ from a catalytic amount of ruthenium dioxide with sodium metaperiodate as the co-oxidant, afforded the desired 26-diethylamino-sulfonyl derivative (98) in good yield. Alternative ruthenium catalysts included ruthenium trichloride or tris(triphenylphosphine)ruthenium(II) chloride. 

Butyrolactones.—A simple method for the direct conversion of protected buty-rolactols into the corresponding butyrolactones is by oxidation with m-chloro-peroxybenzoic acid in the presence of a catalytic amount of boron trifluoride etherate. Yields are usually high but, disappointingly, the method fails with 5-lactols. Unsaturated amide (50) can be converted into the substituted buty-rolactone (51) by treatment with phenyl selenenyl chloride. The generality of this reaction remains to be established. 2-Chloro-4-alkylbutyrolactones (52 X = H or Cl) can be formed from di- or tri-chloroacetic acid respectively and alk-l-enes in the presence of dichlorotris(triphenylphosphine)ruthenium(ii). ... 

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