- Click Reaction of Selenols with Isocyanates: Rapid Access to Selenocarbamates as Peroxide-Switchable Reservoir of Thiol-Peroxidase-Like Catalysts
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Selenols react with isocyanates under mild catalyst-free conditions to generate selenocarbamates in good yield and with high selectivity over potentially competing nucleophilic additions. The methodology enables the incorporation of a wide variety of functional groups providing access to a broad array of densely functionalised selenocarbamates. In the presence of competing heteroatom-centered nucleophiles, isocyanates selectively couple with selenols. Selenocarbamates exhibited thiol-peroxidase-like properties, enabling the reduction of hydrogen peroxide at the expense of thiols, which are converted into the corresponding disulfides. A series of control experiments suggested that the catalytic mechanism proceeds through a pathway, involving a H2O2-promoted transcarbamoylation reaction leading to a thiocarbamate with concomitant releasing of catalytically active selenolate anions. By undergoing peroxide-driven thiol-selenol exchange, selenocarbamates behave as equivalents of selenolate anions with thiol-peroxidase-like activity. (Figure presented.).
- Capperucci, Antonella,Petrucci, Alessandra,Faggi, Cristina,Tanini, Damiano
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supporting information
p. 4256 - 4263
(2021/07/17)
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- Hydrolysis-Based Small-Molecule Hydrogen Selenide (H2Se) Donors for Intracellular H2Se Delivery
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Hydrogen selenide (H2Se) is a central metabolite in the biological processing of selenium for incorporation into selenoproteins, which play crucial antioxidant roles in biological systems. Despite being integral to proper physiological function, this reactive selenium species (RSeS) has received limited attention. We recently reported an early example of a H2Se donor (TDN1042) that exhibited slow, sustained release through hydrolysis. Here we expand that technology based on the P-Se motif to develop cyclic-PSe compounds with increased rates of hydrolysis and function through well-defined mechanisms as monitored by 31P and 77Se NMR spectroscopy. In addition, we report a colorimetric method based on the reaction of H2Se with NBD-Cl to generate NBD-SeH (λmax = 551 nm), which can be used to detect free H2Se. Furthermore, we use TOF-SIMS (time of flight secondary ion mass spectroscopy) to demonstrate that these H2Se donors are cell permeable and use this technique for spatial mapping of the intracellular Se content after H2Se delivery. Moreover, these H2Se donors reduce endogenous intracellular reactive oxygen species (ROS) levels. Taken together, this work expands the toolbox of H2Se donor technology and sets the stage for future work focused on the biological activity and beneficial applications of H2Se and related bioinorganic RSeS.
- Bolton, Sarah G.,Chouinard, Julie E.,Garcia, Arman C.,Golledge, Stephen L.,Newton, Turner D.,Pluth, Michael D.,Zakharov, Lev N.
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p. 19542 - 19550
(2021/11/23)
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- Furfuryl Cation Induced Three-Component Reaction to Synthesize Triazole-Substituted Thioesters
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A furfuryl cation induced three-component thioesterification reaction between thiols, 5-bromo-2-furylcarbinols and azides is reported. This metal-free method relies on the acetyl chloride/HFIP-mediated cascade formal [3+2] cycloaddition/ring-opening/thioesterification, which allows the efficient construction of a series of complex triazole-thioesters linked with an (Z)-olefin. Selenols are also suitable for this strategy. Further derivatization of thioesters highlighted the potential utility of our method.
- Zhong, Ying,Xu, Xiaoming,Xing, Qingzhao,Yang, Song,Gou, Jing,Gao, Ziwei,Yu, Binxun
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supporting information
p. 3251 - 3256
(2020/05/25)
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- Benzylic Thio and Seleno Newman-Kwart Rearrangements
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The thermally induced OBn → SBn and OBn → SeBn migration reactions facilitate the rearrangement of O-benzyl thio- and selenocarbamates [BnOC(=X)NMe2] (X = S or Se) into their corresponding S-benzyl thio- and Se-benzyl selenocarbamates [BnXC(=O)NMe2] (X = S or Se). A series of substituted O-benzyl thio- and selenocarbamates were synthesized and rearranged in good yields of 33-88%. The reaction rates are higher for substrates with electron-donating groups in the 2 or 4 position of the aromatic ring, but the rearrangement also proceeds with electron-withdrawing substituents. The rearrangement follows first-order reaction kinetics and proceeds via a tight ion pair intermediate consisting of the benzylic carbocation and the thio- or selenocarbamate moiety. Computational studies support these findings.
- Eriksen, Kristina,Ulfkj?r, Anne,S?lling, Theis I.,Pittelkow, Michael
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p. 10786 - 10797
(2018/09/06)
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- A77Se NMR study of elemental selenium reduction using NaBH4
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Alkylation or arylation of selenide or diselenide anions is a well-established method to obtain organoselenium compounds. Nevertheless, detecting inorganic selenium anions using77Se NMR is still a challenge. In a previous work, alkylation of Na2Se was found sometimes to yield a mixture of organyl selenides/diselenides in variable amounts. In the literature, this mixture is sometimes attributed to the oxidation of an intermediate alkyl selenol during the extraction. To understand this process, a series of experiments using77Se NMR were performed. It was clear from the77Se NMR experiments that NaHSe-and Se22- formation was very dependent on the NaBH4stoichiometry used. After alkylation, alkyl selenol and dialkyl diselenide were identified, proving they were not formed during the extraction step. As a result, alkyl selenols, dialkyl selenides or dialkyl diselenides with a high purity degree were obtained. To achieve high purity and selectivity of the organoselenium compound, the stoichiometric ratio between Se0/NaBH4has to be carefully measured.
- Oliveira, Alfredo Ricardo Marques De,Piovan, Leandro,Simonelli, Fabio,Barison, Anderson,Santos, Maria De Fatima C.,De Mello, Murilo Belini Marcondes
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- Recyclable 1,2-bis[3,5-bis(trifluoromethyl)phenyl]diselane-catalyzed oxidation of cyclohexene with H2O2: A practical access to trans-1,2-cyclohexanediol
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1,2-Bis[3,5-bis(trifluoromethyl)phenyl]diselane-catalyzed oxidation of cyclohexene by hydrogen peroxide affords a quick, clean and practical access to the important compound trans-1,2-cyclohexanediol under mild conditions. The highly atom-economic properties, clean procedures, high reaction concentration, short reaction time, mild conditions and eco-friendly, recyclable and low loading catalysts facilitate this methodology for possible future practical industrial production. Copyright
- Yu, Lei,Wang, Jun,Chen, Tian,Wang, Yuguang,Xu, Qing
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p. 652 - 656
(2014/08/05)
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- A highly selective, cell-permeable fluorescent nanoprobe for ratiometric detection and imaging of peroxynitrite in living cells
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Peroxynitrite (ONOO-) is a highly reactive species implicated in the pathology of numerous diseases and there is currently great interest in developing fluorescent probes that can selectively detect ONOO- in living cells. Herein, a p
- Tian, Jiangwei,Chen, Huachao,Zhuo, Linhai,Xie, Yanxia,Li, Na,Tang, Bo
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experimental part
p. 6626 - 6634
(2011/07/30)
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- A near-infrared reversible fluorescent probe for peroxynitrite and imaging of redox cycles in living cells
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BzSe-Cy is a small-molecule fluorescent probe containing Se, which can respond reversibly to changes in ONOO- or reduced ascorbate and exhibit high sensitivity and selectivity for ONOO-.
- Xu, Kehua,Chen, Huachao,Tian, Jiangwei,Ding, Baiyu,Xie, Yanxia,Qiang, Mingming,Tang, Bo
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supporting information; experimental part
p. 9468 - 9470
(2011/10/13)
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- Conditions-driven selective synthesis of selenides and selenols from elemental selenium
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Sodium borohydride in DMF is able to reduce elemental selenium in the presence of ethanol. Alkylation of the species resulting from the reaction of 2:1 molar equivalents of NaBH4/Se allows the selective synthesis, under very mild conditions, of symmetrical dialkyl selenides. Addition of formic acid, prior to that of the electrophile, permits the synthesis of the corresponding selenols.
- Krief, Alain,Trabelsi, Mahmoud,Dumont, Willy,Derock, Michel
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p. 1751 - 1754
(2007/10/03)
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- Organoselenium Chemistry. Alkylation of Acid, Ester, Amide, and Ketone Enolates with Bromomethyl Benzyl Selenide and Sulfide: Preparation of Selenocysteine Derivatives
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Bromomethyl benzyl selenide has been prepared and used for the alkylation of several carboxylic acid and amide dianions and certain ketones and ester enolates.Clean reaction could not be achieved for ketones and esters whose alkylation products were subject to selenolate elimination.The selenide reacted 18 times more slowly than bromomethyl benzyl sulfide, which alkylated ketones in fair yield even in some cases where the selenide failed.The bromomethyl benzyl sulfide alkylation products gave α-methylene ketones upon oxidation to sulfoxide and thermolysis.Several protected amino acid enolates (valine, alanine, and glycine) were alkylated with bromomethyl benzyl selenide.The product from glycine, 5b, was converted to the protected dehydroalanine 11 by oxidation and to the protected selenocysteine 10 by using bromine cleavage of the benzyl selenide.Halogen reagents (Br2, SO2Cl2) were shown to very efficiently and generally convert benzyl selenides to selenenyl halides, which were converted to diselenides or selenides by reduction or alkylation.
- Reich, Hans J.,Jasperse, Craig P.,Renga, James M.
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p. 2981 - 2988
(2007/10/02)
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- SYNTHESIS OF SELENOACETALS
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This paper reports our results concerning the syntheses of various bis(alkylseleno)alkanes and some of their arylseleno analogues by different methods.The scope and limitation of each of them are presented.
- Clarembeau, M.,Cravador, A.,Dumont, W.,Hevesi, L,Krief, A.,et al.
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p. 4793 - 4812
(2007/10/02)
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