Dimethylsulfoxide oxidation

FIGURE 1. Examples of reactions catalyzed by molybdenum containing enzymes. From top to bottom, hydroxylation of xanthine, hydroxylation of acetaldehyde, dehydrogenation of carbon monoxide, transhydroxylation of pyrogallol, oxidation of sulfite, reduction of nitrate, reduction of dimethylsulfoxide, oxidation of formate, reduction of polysulfide and formation of formylmethanofuran. 

Torssell, K. Mechanisms of dimethylsulfoxide oxidations. Tetrahedron Lett. 1966, 4445-4451. 

Dimethylsulfoxide oxidation of a-bromomethylquinoxalines yields quinoxalinecarboxaldehydes, and 2,3-bis(bromomethyl)quinoxaline (2) is oxidized by this reagent to the 2,3-dicarboxaldehyde 4. This preparation yields 60% of the cyclic monohydrate 3, which is converted into the dialdehyde by vacuum sublimation. The cyclic monohydrate is also formed by treatment of 2,3-bis(hydroxymethyl)quinoxaline 1,4-dioxide... 

Selenium dioxide oxidation of 2-methylquinoxaline yields quinoxaline-2-carboxaldehyde, and 3-methylquinoxaline-2-carboxaldehyde has been similarly prepared from 2,3-dimethylquinoxaline. Dimethylsulfoxide oxidation of 2,3-bis(bromomethyl)quinoxaline yields the furoquinoxaline 45, and this on sublimation gives quinoxaline-2,3-dicarboxaldehyde. 3-Dibromomethylquinoxaline-2-carboxaldehyde (46) is a by-product of the oxidation reaction. Direct selenium dioxide oxidation of 2,3-dimethylquinoxaline appears to be a less satisfactory method of preparing the dialdehyde. ... 

Vanillin, dimethylsulfide, methyl mercaptan, dimethylsulfoxide - Oxidative process... 

Phosphoryl chloride Carbon disulflde, A,A-dimethylformamide, 2,5-dimethylpyrrole, 2,6-dimethyl-pyridine 1-oxide, dimethylsulfoxide, water, zinc... 

ACPA azobis(4-cyanopentanoic acid) AIBN azobis isobutyronitrile) BPO benzoyl peroxide DVB divinyl benzene, EGA 2-ethylcyano-acrylate HPC hydroxypropyl cellulose MMA methyl methacrylate PAAc polyacrylic acid PEI polyethyleneimine, PEO/PPO polyethylene oxide/polypyropylene oxide copolymer PVME polyvinylmethylether PVP polyvinylpyrrolidone K-30 DMSO dimethylsulfoxide PGA polyglutaraldehyde CMS chloromethylstyrene PMMA-g-OSA polymethylmethacrylate grafted oligostearic acid. 

Vat dyes (the best known are Tyrian purple, indigo and woad) are insoluble in water. Before dyeing, they must be reduced into water-soluble leucoforms. After impregnation of the textile, dyestuffs are again oxidized into colour forms. As far as their extraction is concerned, aprotic solvents are usually recommended, e.g. pyridine, dimethylformamide or dimethylsulfoxide. 

More recently, this method has been extended to preparation of a variety of disulfonium dications from both acyclic and cyclic bis-sulfides, including very labile dications not observed when other methods were used.78 Thus, simple acyclic S-S dications were prepared by an intermolecular reaction of a monosulfide, a monosulfoxide and triflic anhydride.79 In the first step, reaction of triflic anhydride with dimethylsulfoxide generates a highly electrophilic80 complex 50 (dimethyl sulfide ditriflate).81 The latter reacts with dimethyl sulfide to give labile tetramethyldisulfonium dication 51 identified by NMR spectroscopy.79 In a similar manner, bis-(tetramethylene)disulfonium dication 52 is obtained from tetrahydrothiophene and its S-oxide (Scheme 17). 

The hydrophobicity of the solvent and solution composition [as example, the (])cl of luminol oxidized in dimethylsulfoxide (DMSO) is 0.05 compared with 0.01 in water, the colors being blue-violet (425 nm) and blue-green (480-502 nm), respectively]... 

Iron complexes or microsomal nonheme iron are undoubtedly obligatory components in the microsomal oxidation of many organic compounds mediated by hydroxyl radicals. In 1980, Cohen and Cederbaum [27] suggested that rat liver microsomes oxidized ethanol, methional, 2-keto-4-thiomethylbutyric acid, and dimethylsulfoxide via hydrogen atom abstraction by hydroxyl radicals. Then, Ingelman-Sundberg and Ekstrom [28] assumed that the hydroxylation of aniline by reconstituted microsomal cytochrome P-450 system is mediated by hydroxyl radicals formed in the superoxide-driven Fenton reaction. Similar conclusion has been made for the explanation of inhibitory effects of pyrazole and 4-methylpyrazole on the microsomal oxidation of ethanol and DMSO [29],... 

Palladium Paraformaldehyde Paraldehyde Pentaborane-9 Pentacarbonyliron Arsenic, carbon, ozonides, sulfur, sodium tetrahydridoborate Liquid oxygen Alkalies, HCN, iodides, nitric acid, oxidizers Dimethylsulfoxide Acetic acid, nitric oxide, transition metal halides, water, zinc... 

Phosphorus pentafluoride Phosphorus pentasulfide Phosphorus pentoxide Phosphorus, red Phosphorus tribromide Phosphorus bichloride Water or steam Air, alcohols, water Formic acid, HF, inorganic bases, metals, oxidants, water Organic materials Potassium, ruthenium tetroxide, sodium, water Acetic acid, aluminum, chromyl dichloride, dimethylsulfoxide, hydroxylamine, lead dioxide, nitric acid, nitrous acid, organic matter, potassium, sodium water... 

Sulfides Sulfur Sulfur dioxide Sulfuric acid Sulfuryl dichloride Acids, powerful oxidizers, moisture Oxidizing materials, halogens Halogens, metal oxides, polymeric tubing, potassium chlorate, sodium hydride Chlorates, metals, HC1, organic materials, perchlorates, permanganates, water Alkalis, diethyl ether, dimethylsulfoxide, dinitrogen tetroxide, lead dioxide, phosphorus... 

The NMR spectrum shown in Figure 5 was obtained by dissolving hydralazine hydrochloride in deuterium oxide containing 3-(trimethylsilyl)-1-propane-sulfonic acid sodium salt (DSS). The series of peaks at 0, 0.6, 1.8, and 3 ppm are all due to the DSS. The peak at 4.8 ppm is due to HDO which forms on exchange with the solvent and the peaks at 8.01 and 8.61 ppm are due to the aromatic protons. The NMR spectrum of the base (Figure 6) was obtained in a 1 1 mixture of dimethylsulfoxide-d,- deuterochloroform. 

The primary synthetic route proceeds via oxidative dimerization of 2-aminoan-thraquinone in the presence of an alkali hydroxide. 2-aminoanthraquinone, for instance, is fused with potassium hydroxide/sodium hydroxide at 220 to 225°C in the presence of sodium nitrate as an oxidant. New techniques involve air oxidation of 1-aminoanthraquinone at 210 to 220°C in a potassium phenolate/sodium acetate melt or in the presence of small amounts of dimethylsulfoxide. A certain amount of water which is formed during the reaction may be removed by distillation in order to improve both efficiency and yield. 

In the case of the DMSO reductase family, as pointed out above, the metal centre is bound to two molecules of the cofactor. DMSO reductase itself catalyses the reduction of dimethylsulfoxide to dimethylsulfide with incorporation of the oxygen atom of DMSO into water. The active site of the oxidized enzyme is an L2MoVI0(0-Ser) centre, which, upon reduction, loses the M=0 ligand to give a L2MoIV(0-Ser) centre. In the catalytic... 

These include hydrazine, dimethylsulfoxide (DMSO), formamide and some derivatives (N-methylformamide and dimethylformamide), acetamide and some derivatives, and pyridine N-oxide. Some salts such as potassium acetate also intercalate kaolinites. Once intercalated by one of these small molecules or salts, other molecules which normally do not directly intercalate kaolins can be introduced by replacement. Further, the exposure of the inner surfaces by intercalation gives one the opportunity to alter the interlayer bonding of the kaolin layers by chemical modification of the inner surfaces. 

For many species and solvents these assumptions are thought to be sensible, whereas in some cases they may lead to significant errors (see following discussion). Nevertheless, this was the approach used by Bordwell and co-workers [342], They combined most of the terms of equation 16.32 in a single constant, C, which was empirically adjusted to give better agreement with gas-phase data [343-345], Equation 16.33 illustrates this procedure C = 306.7 kJ mol-1 is valid for S = dimethylsulfoxide (DMSO) and when the oxidation potential of R- is anchored on the ferrocenium/ferrocene Fc+/Fc) couple instead of the SHE in water. 

J. Zhou, H. Xu, G.-H. Wan, C.-F. Duan and H. Cui, Enhancing and inhibiting effects of aromatic compounds on luminol-dimethylsulfoxide-OH chemiluminescence and determination of intermediates in oxidative hair dyes by HPLC with chemiluminescence detection. Talanta, 64 (2004) 467—477. 

High-spin, five-coordinate complexes are known of type [MnLXJPFg (X = F, Cl, Br, or I and L = 2,9-dimethyl-3,10-diphenyl-1,4,8,11-tetraazacyclotetra-l,3,8,10-tetraene). Electrochemical investigation of these complexes revealed that they are surprisingly resistant to oxidation in dimethylsulfoxide." ... 

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