Hydrogen peroxide-Selenium dioxide

ALLYLIC OXIDATION WITH HYDROGEN PEROXIDE-SELENIUM DIOXIDE frans-PINOCARVEOL... 

A highly selective and rapid oxidation of sulphides to sulphoxides occurs when hydrogen peroxide/selenium dioxide system is used32. The reaction takes place immediately upon addition of a solution of hydrogen peroxide and selenium dioxide to a solution of a sulphide in methanol at room temperature. Yields of sulphoxides (Table 2) are in the range between 80 and 95%. It is most probable that perseleninic acid 19 is the true oxidizing agent. 

Hydrogen peroxide-Selenium dioxide, 244 2-Hydroperoxyhexafluoro-2-propanol, 244-245... 

Treatment of cyclobutanone under aqueous acidic conditions with either hydrogen peroxide/selenium dioxide or thallium(III) salts gives cyclopropanecarboxylic acid in a good yield (equation 176) ... 

Hydrogen peroxide-Selenium dioxide. A. Stoll effected olefin hydroxylations with hydrogen peroxide in combination with a stochiometric amount of selenium dioxide in... 

Hydroxylation Boric acid (see Diborane). Hydrogen peroxide. Hydrogen peroxide-Osmium tetroxide. Hydrogen peroxide-Selenium dioxide. Osmium tetroxide. Osmium tetroxide-Barium chlorate. Peracetic acid. Perbenroic acid. Persucdnic acid. Pertrifluoroacetic acid. Potassium permanganate. Potassium persulfate. Selenium dioxide. Silver acetate. Silver chlorate. 

OXU3ATIVE Hydrogen peroxide. Hydrogen peroxide-Selenium dioxide. Lead tetraacetate. Photolytic Cuprous chloride. 

EPOXIDATION m-Chloroperbenzoic acid. Hydrogen peroxide, basic. Hydrogen peroxide—Phenylisocyanate. Hydrogen peroxide-Selenium dioxide. Iodine. Peracetic acid. Perlauric acid. Tetralin hydroperoxide. Vanadium oxyacetyl-acetonate. 

ALLYLIC OXIDATION f-Butyl hydro-peroxide-Selenium dioxide. Chromic anhydride-3,5-Dimethylpyrazole. Selenium dioxide-Hydrogen peroxide. 

The preparation of Pans-1,2-cyclohexanediol by oxidation of cyclohexene with peroxyformic acid and subsequent hydrolysis of the diol monoformate has been described, and other methods for the preparation of both cis- and trans-l,2-cyclohexanediols were cited. Subsequently the trans diol has been prepared by oxidation of cyclohexene with various peroxy acids, with hydrogen peroxide and selenium dioxide, and with iodine and silver acetate by the Prevost reaction. Alternative methods for preparing the trans isomer are hydroboration of various enol derivatives of cyclohexanone and reduction of Pans-2-cyclohexen-l-ol epoxide with lithium aluminum hydride. cis-1,2-Cyclohexanediol has been prepared by cis hydroxylation of cyclohexene with various reagents or catalysts derived from osmium tetroxide, by solvolysis of Pans-2-halocyclohexanol esters in a manner similar to the Woodward-Prevost reaction, by reduction of cis-2-cyclohexen-l-ol epoxide with lithium aluminum hydride, and by oxymercuration of 2-cyclohexen-l-ol with mercury(II) trifluoro-acetate in the presence of ehloral and subsequent reduction. ... 

A mixture of 1,4-dioxane and water is often used as the solvent for the conversion of aldehydes and ketones by H2Se03 to a-dicarbonyl compounds in one step (Eq. 8.117).331 Dehydrogenation of carbonyl compounds with selenium dioxide generates the a, (i-unsaturated carbonyl compounds in aqueous acetic acid.332 Using water as the reaction medium, ketones can be transformed into a-iodo ketones upon treatment with sodium iodide, hydrogen peroxide, and an acid.333 Interestingly, a-iodo ketones can be also obtained from secondary alcohol through a metal-free tandem oxidation-iodination approach. 

Oxidation of 2,3-dimethylquinoxaline (from phenylenediamine and diacetyl) with either peracids or hydrogen peroxide in acetic acid gives the 1,4-dioxide (162). Treatment of this bis-N-oxide with selenium dioxide leads to oxidation of one of the methyl groups to the methyl carbinol and formation of... 

Treatment of 73 with selenium metal at 360° yields dibenzothio-phene. Oxidation of 73 with hydrogen peroxide was accompanied by partial dehydrogenation yielding 1,2,3,4-tetrahydrodibenzothiophene 5,5-dioxide (68). ... 

The pyrazine ring is stable toward permanganate oxidation, and this explains a variety of pyrazinecarboxylic acids that have been prepared from quinoxalines or benzo-fused quinoxalines. In contrast, alkyl side chains on pyrazines are effectively oxidized by permanganate, selenious acid, selenium dioxide, or dichromate to afford the corresponding carboxylic acids (Section 8.03.7.1). Oxidation of pyrazines with hydrogen peroxide or percarboxylic acids gives pyrazine A -oxides and/or A, A -dioxides (Section 8.03.5.2). 

A double oxidation at the 5,6-carbon-carbon double bond and N-9 by 2equiv of OT-chloroperbenzoic acid (MCPBA) was postulated as the mechanism for the oxidative rearrangement of 8-dialkylaminoxanthines to novel l-oxo-2,4,7,9-tetraazaspiro[4,5]dec-2-ene-6,8,10-triones <1999EJ02419>. The presence of an electron-donating 8-amino substituent was essential for this reaction to occur. Further oxidation of the products gave 1,3-dimethylpara-benic acid 45, which was also produced directly when selenium dioxide or hydrogen peroxide were used (Scheme 11). 

Oxidation of the sulfur- or selenium-bridged azepines (171 X=S or Se) with mercury(II) oxide in methanol yields ultimately the 4f/-azepine (68JCS(C)23ll) with hydrogen peroxide as oxidant, the sulfur compound furnishes the sulfoxide (171 X=SO). Selenium dioxide oxidation of 7,8-dimethyl-lf/-l-benzazepin-2-one affords the 2,3-dioxo derivative (173) that displays no evidence of enol tautomers or heteroaromaticity (7ici(L)1439). 

Phenanthrenequinone has been prepared by treatment of phe-nanthrene with chromic acid in acetic acid 5 potassium dichromate in sulfuric acid 3-6 hydrogen peroxide in acetic acid 6 7 and selenium dioxide above 250°.8 It can also be prepared from benzil with aluminum chloride at 120° 9 and from biphenyl-2,2 -dialdehyde with potassium cyanide.10... 

Many other oxidising agents can effect the same change in a thiosulphate, for example permanganates,3 chlorates,4 selenium dioxide,5 barium peroxide,8 hydrogen peroxide 7 and lead dioxide, in the presence of sufficient sulphuric acid to neutralise the alkali as it is produced ... 

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