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Hydroperoxide Oxidation of Different Organic Compounds Catalyzed by Silica-Supported Selenenamide

Giurg M., Brząszcz M., Młochowski J.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 3

417-428

EN

The recoverable heterogeneous silica-supported catalyst selenenamide 2 was prepared by the coupling of 3-aminopropylsilicate (4)with 2-chloroselenobenzoyl chloride (6). Its catalytic activity was demonstrated in tert-butyl hydroperoxide oxidation of aldehydes 8 to carboxylic acids 9 and benzylamines 17 to nitriles 18. Moreover, it was employed for hydrogen peroxide oxidation of azomethine compounds such as tosylhydrazones 10, oximes 13 and N,N-dimethylhydrazones 16 to parent ketones 12, arenecarboxylic acids 11 and 15, their methyl esters 14 and nitriles 18 depending on the substrate used and the reaction conditions. The catalystwas simply recovered by filtration and could be reused.

2

A New Approach to Synthesis of Questiomycin A: Oxidative Cyclocondensation of ortho-Aminophenol

Giurg M., Wiech E., Piekielska K., Gębala M., Młochowski J., Wolański M., Ditkowski B., Peczyńska-Czoch W.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 2

297-306

EN

Oxidation of ortho-aminophenol (1) to 2-amino-3H-phenoxazin-3-one (2) by air,manganese( IV) oxide, hydrogen peroxide or tert-butylhydroperoxide in the presence of different activators including such enzymes as laccase and peroxidase was studied. The most effective oxidants were air/Co(salen), MnO2/2,6-dicarboxypyridine complex 3k, H2O2/ebselen, H2O2/2,2'-dicarbamoylphenyldiphenyl disenide and TBHP/diphenyl diselenides 4d and 4e. Laccase and peroxidase were less active agents. The six-electron cyclocondensation mechanism is discussed.

3

The Reactions of 2-(Bromoseleno) benzenesulfonyl Chloride with Primary Amines toward 2,2'-Diselenobis(benzenesulfonamides) and 1,2,3-Benzothiaselenazole 1,1-Diodides: New oxygen-Transfer Agents, Antimicrobials and Virucides

Potaczek P., Giurg M., Kloc K., Maliszewska I., Piasecki E., Piętka M., Młochowski J.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 5

687-697

EN

The reaction of title compound 6 with primary aliphatic or aromatic amines was investigated. The products were 2,2_-diselenobis(benzenesulfonamides) (4) accompanied in some cases by 1,3,2-benzothiaselenazole 1,1-dioxides (3). Exceptionally, when aniline was a reagent, 2-(sulfamoylphenyl)phenylselenenylanilide was produced. These results are interpreted in the light of the proposed mechanisms. The compounds 3 and 4 exhibited catalytic activity in hydroperoxide oxidation of cyclohexanone (12) and 1-naphthaldehyde N,N-dimethylhydrazone (17). Although they were inactive against patogenic bacteria and fungi an appreciable antiviral activity against HSV-1 and EMCV of the compounds 3b, 3c and 4b was observed.

4

Hydrogen Peroxide Oxidation of Naphthalene Derivatives Catalyzed by Poly(bis-1,2-diphenylene) Diselenide

Giurg M., Syper L., Młochowski J.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 2

231--248

EN

Oxidation of 1- and 2-substituted naphthalenes (1) with 30% hydrogen peroxide in the presence of poly(bis-1,2-diphenylene) diselenide (PPDS) has been investigated. Depending on the substrate used trans-2-carboxycinnamic acid (2), and its isomer, (1-oxo-1,3-dihydroisobenzofuran-1-yl)acetic acid (3) or 2-naphthoic acid (4b) was a major product. Oxidation of hydroxynaphthalenes 1b and 1c is a convenient way to obtain trans-2-carboxy cinnamic acid (2) in almost quantitative yield. The mechanism of the reaction is postulated.

5

Hyrdoperoxide Oxidation of Azomethines and Alkylarenes Catalyzed by Ebselen

Giurg M., Wójtowicz H., J. Młochowski J.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 4

537-542

EN

2-Phenyl-1,2-benzisoselenazol-3(2H)-one (ebselen), known as glutathione peroxidase mimic, is found as an efficient catalyst for hydrogen peroxide and tert-butyl hydroperoxide oxidation of the azomethine group in azines, aldoximes, and methyl or methylene group in alkylarenes. Depending on the substrate used and the reaction conditions, the major products are aldehydes, ketones, carboxylic acids or their derivatives. It is postulated that ebselen is involved in the free-radical oxidation mechanism.

6

Hydrogen Peroxide Oxidation of N,N-Dimethylhydrazones Promoted by Selenium compounds, Titanosilicalites or Acetonitrile

Giurg M., Młochowski J., Ambrożak A.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 12

1713-1720

EN

Hydrogen peroxide oxidation of N,N-dimethylhydrazones 1 promoted by title reagents has been investigated. Depending on the substrate nitrile 2 and/or amide 3 accompanied with carboxylic acid 4 and parent carbonyl compounds 5 were obtained. Formation of nitriles 2 with H2O2-acetonitrile system is limited for a few more active substrates. The mechanism of the reaction, based on generated in situ peroxyiminoacetic acid, is presented. A broad spectrum of aliphatic, unsaturated and aromatic nitriles 2 was obtained by oxidation of corresponding N,N-dimethylhydrazones 1 with hydrogen peroxide in the presence of poly(bis-9,10-anthracenyl) diselenide (PADS) (7) as catalyst.

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Związki selenu jako odczynniki i katalizatory w reakcjach utleniania związków organicznych

Młochowski J., Brząszcz M., Giurg M., Wójtowicz H.

Wiadomości Chemiczne

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2001

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[Z] 55, 1-2

9-44

EN

Oxidation reactions are fundamental processes widely applied in organic synthesis. Among many reagents used in these reactions, elemental selenium and particularly some of its compounds have been reported as effective and selective oxidants and catalysts for the oxidation of various organic substrates. One of them is selenium(IV) oxide, easily available regent for hydroxylation of activated a-positions particularly at allylic and propargylic sites. It also can introduce carbonyl functionality at activated positions. Used in combination with hydrogen peroxide or t-butylhydroperoxide it acts as oxygen-transfer agent. Both of these hydroperoxides can be used in the presence of seleniumu(IV) oxide for epoxidation, 1,2-dihydroxylation and a-carbonylation of alkenes, for oxidation of aldehydes into carboxylic acids, sulfides to sulfoxides or sulfones, secondary amines to nitrones and for other reactions. Benzeneseleninic acid, other areneseleninic acids and their anhydrides are known as stoichiometric oxidants or activators of other oxygen donors. They have been successfully applied for oxidation of many organic compouns, among them alkenes, alcohols, phenols, amines, hydrazones, sulfides, 1,3-dithiolanes and azines. Organic diselenides, the precursors of seleninic acids, have been used as oxygen-transfer catalysts for oxidation of various functional groups with hydrogen peroxide, t-butylhydroperoxide and other oxygen donors , while dimethyl and diphenyl selenoxides are efficient stoichiometric oxidants (e.g. for conversion of halomethyl or hydroxymethyl group into formyl group]. Most recently, selenenamides, particularly 2-phenyl-1,2-benzisoselenazol-3(2H)-one (ebselen) and its analogous were found as efficient catalysts for hydrogen peroxide and tbutylhydroperoxide oxofunctionalization of olefins, oxidation of azomethine compounds and sulfides.