Hydrogen peroxide DMSO oxidation

Ethers of benzenepentol have been obtained by Dakin oxidation of the appropriately substituted acetophenone. Thus, the oxidation of 2-hydroxy-3,4,6-ttimethoxyacetophenone and 2-hydroxy-3,4,5-ttimethoxyacetophenone with hydrogen peroxide ia the presence of alkali gives l,2-dihydroxy-3,4,6-ttimethoxybenzene and l,2-dihydroxy-3,4,5-ttimethoxybenzene, respectively further methylation of these ethers yields the pentamethyl ether of benzenepentol (mp 58—59 degC) (253). The one-step aromatization of myoinositol to produce esters of pentahydroxybenzene is achieved by treatment with carboxylic acid anhydrides ia DMSO and ia the presence of pyridine (254) (see Vitamins). 6-Alkyl- or... 

Finally, the hydrazide 29 98> is strongly fluorescent in neutral solution (e.g. in dioxane), the fluorescence intensity amounting to about 200% of that of 7-dimethylamino-naphthalene-1.2 dicarboxylic hydrazide 30, which is one of the best chemiluminescent hydrazides 97b The 5-isomer, however, is very poor in chemiluminescence in an aqueous system (hemin-catalyzed oxidation with aqueous alkaline hydrogen peroxide), the light yield being only 1 % of that of the 7-isomer in DMSO/t-Bu0K/02 its quantum yield is slightly better but very distinctly below that of 30 98>">. It should be mentioned that in aqueous alkaline solu-... 

The oxidation of thioamides 63 with a wide variety of oxidizing agents is a well-employed method for the synthesis of 3,5-disubstituted-l,2,4-thiadiazoles 64 <1982AHC285>. However, this method is limited mainly to arylthioamides. The most common oxidizing agents tend to be halogens, hydrogen peroxide, dimethyl sulfoxide (DMSO), and nitrous acid. Yields from these reactions are variable and depend on the thioamide, oxidant, and conditions used (Equation 19). By-products such as nitriles and isothiocyanates are usually formed. 

Oxidation of Potassium Peroxide. Determination of Potassium Superoxide. Potassium peroxide was prepared by the addition of a tert-butyl alcohol solution of 90% hydrogen peroxide to potassium tert-butoxide in DMSO or tert-butyl alcohol. Oxygen absorption was followed in the standard manner (20). Analysis of solid precipitates for potassium superoxide followed exactly the method of Seyb and Kleinberg (23). Potassium superoxide formed in the oxidation of benzhydrol was determined in a 15-ml. aliquot of the oxidation solution. To this aliquot 10 ml. of diethyl phthlate was added to prevent freezing of the solution. The mixture was cooled to 0°C., and 10 ml. of acetic acid-diethyl phthlate (4 to 1) added over a period of 30 minutes with stirring. The volume of the evolved oxygen was measured. 

Oxidation of DMS to DMSO and DMSO. DMS is chemically and biochemically oxidized to dimethylsulfoxide (DMSO). Mechanisms for the in situ oxidation of DMS to DMSO in seawater have received little attention, even though this may be an important sink for DMS. Hydrogen peroxide occurs in surface oceanic waters (22) and is produced by marine algae (98). It may participate in a chemical oxidation of DMS, since peroxide oxidizes sulfides to sulfoxides (991. Photochemical oxidation of DMS to DMSO occurs in the atmosphere and DMSO is found in rain from marine regions (681. DMS is also photo-oxygenated in aqueous solution to DMSO if a photosensitizer is present natural compounds in coastal seawater catalyzed photo-oxidation at rates which may be similar to those at which DMS escapes from seawater into the atmosphere (1001. 

Methanesulfonic acid, dimethyl sulfoxide and dimethyl sulfone are potential intermediates in the gas phase oxidation of dimethylsulfide in the atmosphere. We nave measured the rate of reaction of MSA with OH in aqueous solution using laser flash photolysis of dilute hydrogen peroxide solutions as a source of hydroxyl radicals, and using competition kinetics with thiocyanate as the reference solute. The rate of the reaction k (OH + SCN ) was remeasured to be 9.60 1.12 x 109 M 1 s 1, in reasonable agreement with recent literature determinations. The rates of reaction of the hydroxyl radical with the organosulfur compounds were found to decrease in the order DMSO (k = 5.4 0.3 x 109 M-i s 1) > MSA (k = 4.7 0.9 x 107 M l S 1) > DMS02 (k = 2.7 . 15 x 107 M 1 s ). The implications of the rate constant for the fate of MSA in atmospheric water are discussed. 

Form Supplied in (1) white solid commercially available. Preparative Methods excess DMSO containing Copper(II) Chloride (or another copper catalyst) is treated with Chloramine-T trihydrate. (1) is obtained in 90% yield after aqueous EDTA workup and recrystallization from ethanol.The other A-tosylsulfoximines can be prepared by the tosylation of N-H sul-foximines with p-Toluenesulfonyl Chloride in the presence of base, but the two most useful and general methods are the oxidation of Af-tosylsulfilimines with basic Hydrogen Peroxide, ... 

Oxiranes can be converted to dialdehydes with hydrogen peroxide in the presence of a boric acid ester or phosphoric acid ester.The base-catalyzed oxidation of oxirane and alkyl-substituted oxiranes with fcA-r-butylhydroperoxide has been reported. With increased substitution the molecule undergoes fragmentation. With DMSO in the presence of terf-butylhydroperoxide and strong acids, a-ketols are formed via a sulfonium salt (Eq. 156). ... 

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... 

Fig. 18. Influence of 6-hydroxybenzothiazole on light emission from the peroxidase conjugate-catalyzed oxidation of luminol. Anti-AFP-HRP conjugate (10 pi) and the enhancer (20 pi of a DMSO solution) were placed in separate comers of a cuvette. Luminescence was triggered by adding 1 ml of luminol (60 pM) and hydrogen peroxide (2 mM) in Tris buffer at pH 8.5. Data points represent peak light emissions from intensity-time curves. Taken from Thorpe et al. (T11) with permission.

SILVER FLUORIDE or SILVER(I) FLUORIDE or SILVER MONOFLUORIDE (7775-41-9) AgF AgF HOH Moisture- and light-sensitive, hygroscopic, corrosive solid. Contact with acetylene produces silver acetylide, a shock-sensitive explosive material. Contact with ammonia produces conpounds that are explosive when dry. Contact with hydrogen peroxide causes violent deconposition and release of oxygen gas. Contact with boron, strong oxidizers may cause fire and explosions. Violent reaction when mixed with calcium hydride (fiiction sensitive) dimethyl sulfoxide (DMSO) silicon. Soluble silver compounds attack some forms of plastics, rubber, and coatings. 

An unavoidable by-product of the Swem reaction is the volatile dimethylsulphide which, on account of its unpleasant smell, is a reagent regulated by offensive odour control laws. This makes large scale chemistry problematic, especially in industry. To overcome this, several methods exist to perform the Swem oxidation under odourless conditions. For example, Node et al. outline a protocol for the Swem oxidation which uses dodecyl methyl sulfoxide in place of methyl sulfoxide,12 while Crich and co-workers have developed a fluorous Swem oxidation reaction that uses tridecafluorooctylmethyl sulfoxide 17,l3a,b This reagent can be recovered via a continuous fluorous extraction procedure and recycled by reoxidation with hydrogen peroxide. Additionally, the fluorous DMSO is crystalline, odourless and soluble in CH2CI2 to —45 °C. 

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