- Singlet oxygen oxidation of selenides to selenoxides
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The presence of water and a carbonate proved to be highly beneficial for singlet oxygen oxidation of selenides to selenoxides.
- Krief, Alain,Lonez, Frédéric
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- Selenoxides inhibit δ-aminolevulinic acid dehydratase
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The effect of two selenides and their selenoxides on δ-aminolevulinic acid dehydratase (δ-ALA-D) from liver of adult rats was investigated. In vivo, selenides can be oxidized to selenoxides by flavin-containing monooxygenases (FMO) and selenoxides can regenerate selenides by thiol oxidation. Phenyl methyl selenide (PhSeCH3) and 1-hexynyl methyl selenide (C4H9C≡CSeCH3) were converted to selenoxides by reaction with H2O2. PhSeCH3 and C4H9C≡CSeCH3 had no effect on δ-ALA-D up to 400 μM. Conversely, their selenoxides inhibited δ-ALA-D, and the IC50 for enzyme inhibition was about 100 and 70 μM, respectively. Partially purified δ-ALA-D (P55) from swine liver was also inhibited by these selenoxides. The inhibitory action of selenoxides was antagonized by dithiotreitol (DTT). Moreover, δ-ALA-D from a plant source was inhibited by the selenoxides, suggesting a possible involvement of -SH groups in a distinct site of the homologous region implicated in Zn2+ binding in mammalian δ-ALA-D. After exposure to PhSeCH3 (500 μmol/kg/day) for 45 or 30 days, the activity of δ-ALA-D from liver of mice decreased to about 50% of the control group. The in vivo inhibitory action of this compound was not antagonized by DTT. PhSeCH3 and C4H9C≡CSeCH3 had no effect on the rate of DTT oxidation, but their selenoxides oxidized DTT. The results of the present study suggest that hepatic δ-ALA-D of rodents is a potential molecular target for selenides as a consequence of their metabolism to selenoxides by FMO.
- Farina, Marcelo,Folmer, Vanderlei,Bolzan, Rodrigo C,Andrade, Leandro H,Zeni, Gilson,Braga, Antonio L,Rocha, Joao B.T
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- Metal-Free Synthesis of Selenodihydronaphthalenes by Selenoxide-Mediated Electrophilic Cyclization of Alkynes
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A transition-metal-free, selenium mediated electrophilic cyclization reaction was realized through a one-pot procedure between simple alkynes and triflic anhydride-activated selenoxides to give selenium containing dihydronaphthalene products. This method gave good to very high yields for all products, including selenium-substituted phenanthrene, dihydroquinoline, 2H-chromene, and coumarin, which can be further transformed to other functionalized compounds.
- An, Shaoyu,Li, Pingfan,Zhang, Zhong
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p. 3059 - 3070
(2021/07/22)
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- Synthesis of Selenoxides by Oxidation of Selenides with t-Butyl Hypochlorite, and Its Application for Synthesis of Optically Active Selenoxide
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An effective synthesis of selenoxides by the oxidation of selenides with t-butyl hypochlorite in the presence of methanol and pyridine followed by hydrolysis is described.This oxidation method is particularly effective for the oxidation of selenides which possess electron-withdrawing groups.A synthesis of partially optically active selenoxide with bulky substituents can be achieved using a novel oxidation method.
- Kobayashi, Michio,Ohkubo, Hiromi,Shimizu, Toshio
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p. 503 - 506
(2007/10/02)
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- ASYMMETRIC OXIDATION OF ACHIRAL SELENIDES TO OPTICALLY ACTIVE SELENOXIDES. STEREOCHEMISTRY OF THE ALLYL SELENOXIDE-SELENENATE SIGMATROPIC REARRANGEMENT
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Asymmetric oxidation of methyl phenyl selenide (3), under anhydrous conditions, by chiral 2-sulfonyloxaziridines, 1-2, give optically active methyl phenyl selenoxide (8.1-9.3percent ee).The stereochemistry of the selenoxide is determined by the configuration of the oxaziridine three membered ring with nonbonded steric interactions responsible for the chiral recognition.Asymmetric oxidation of E-phenyl cinnamyl selenide (7) by 1-2 affords optically active 1-phenylallyl alcohol (9).A concerted sigmatropic rearrangement via an exo transition state is proposed.
- Davis, Franklin A.,Stringer, Orum D.,McCauley, John P., Jr.
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p. 4747 - 4758
(2007/10/02)
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- FUNCTIONAL GROUP DIVERSITY IN ENZYMATIC OXYGENATION REACTIONS CATALYZED BY BACTERIAL FLAVIN-CONTAINING CYCLOHEXANONE OXYGENASE
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The bacterial flavoprotein monooxygenase cyclohexanone oxygenase was found by spectrophotometric NADPH consumption assays and product analysis to perform oxygenation reaction on ketones, aldehydes, sulfides, selenides, boronic acids, a phophite ester, and an iodide ion.Kinetic parameters (Km, Vmax) are reported for these substrates.The relevance of these results to possible active oxygen-transfer species in this enzyme is discussed.The potential utility of boronic acids as general probes for nucleophilic oxygen-transfer capability in oxygenases and in model chemistry is analyzed.The potential utility of cyclohexanone oxygenase as a n enantioselective and/or chemoselective oxidant for organic molecules is assessed.Unsuccessful attempts at exploiting the 2,3-sigmatropic rearrangement of allyl sulfoxides and allyl selen oxides for mechanism-based inactivation of cyclohexanone oxygenase are reported.The use of the facile 2,3-sigmatropic rearrengement of allyl selenoxides to generate electrophilic allyl selenates for the design of mechanism-based inactivators for other enzymes is proposed.
- Branchaud, Bruce P.,Walsh, Christopher T.
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p. 2153 - 2161
(2007/10/02)
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- SYNTHESIS, STRUCTURE, AND PROPERTIES OF COMPOUNDS WITH A CHALCOGEN-NITROGEN BOND. V. N-TRIFLUOROACETYL-Se-ARYL-Se-METHYLSELENIMIDES
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The IR and UV spectra of a series of N-trifluoroacetyl-Se-aryl-Se-methylselenimides were studied.The molecules of these compounds, like those of N-acylsulfimides and N-acyltelurimides with similar structures, have a bipolar structure, in which the negative charge is distributed through the bond system of the N-trifluoroacetyl group.
- Naddaka, V. I.,Krasnov, V. P.,Minkin, V. I.
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p. 432 - 436
(2007/10/02)
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- OXIDATION OF SELENIDES TO SELENOXIDES USING 2-SULFONYLOXAZIRIDINES
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Application of 2-sulfonyloxaziridine, 9, for the "one-pot" transformation of selenides to alkenes and the rearrangement of allylic selenides to allylic alcohols are described.
- Davis, Franklin A.,Stringer, Orum D.,Billmers, Joanne M.
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p. 1213 - 1216
(2007/10/02)
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- PREPARATION AND REACTION OF N-TOSYL- AND N-ACYLSELENILIMINES
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N-Tosyl-Se,Se-diphenylselenilimines (Ia, hydrate state (Ib) of Ia), N-tosyl-Se-methyl-Se-phenylselenilimines (Ic), N-tosyl-Se,Se-dialkylselenilimines (Id-f), N-acyl-Se-aryl-Se-phenyl-selenilimines (IIa-e) and N-acyl-Se,Se-dibenzylselenilimine (IIf) were prepared.The pyrolyses of selenilimines (Ia, d, e, IIa-e) proceeded more readily than those of the corresponding sulfur derivatives.The pyrolyses of N-acyl-Se-aryl-Se-phenylselenilimines gave the corresponding isocyanates in good yields after treatment of the reaction mixture with aniline, together with aryl phenyl selenide.A ki netic study revealed that the rate of pyrolysis of N-benzoyl-Se,Se-diphenylselenilimine (IIa) was 300 times faster than that of the corresponding sulfilimine.The activation enthalpy and entropy were ΔH* = 32.1 kcal/mol and ΔS* = 1.2 e.u. respectively for Ph2Se -> NCOPh.Oxidations of N-tosyl- and N-benzoyl-Se,Se-diphenylselenilimine were carried out with hydrogen peroxide or potassium permanganate to obtain the corresponding selenoxides or selenones, respectively.Hydrolysis of N-tosyl- and N-benzoyl-Se,Se-diphenylselenilimines also took place more readily than that of the corresponding sulfilimines and the selenoxides and the amides were obtained in good yields at room temperature.When N-tosyl-Se,Se-pentamethyleneselenilimine (Ie) was treted with conc. sulfuric acid, a selenurane, Se-hydroxy-Se-(hydroxysulfoxy)selenane (III) was obtained in a high yield.
- Oae, Shigeru,Fukumura, Mitsuo,Furukawa, Naomichi
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p. 153 - 162
(2007/10/02)
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