The synthesis, structure, and thiol peroxidase-like antioxidant activities of several diaryl diselenides having intramolecularly coordinating amino groups are described. derived from enantiomerically pure R-(+)- S-(-)-N,N-dimethyl(1-ferrocenylethyl)amine show excellent peroxidase activity. To investigate the mechanistic role various organoselenium intermediates, a detailed in situ characterization intermediates has been carried out by (77)Se NMR spectroscopy. While most exert their activity...

Chiral and achiral organochalcogen compounds bearing a heteroatom in close proximity are easily accessible via the directed aromatic lithiation route. The lithium chalcogenolates prepared by insertion of selenium or tellurium into C-Li bond used to synthesize various chalcogen such as Se/Te, N donor ligands, dichalcogenides, monomeric metal chalcogenolates, macrocycles. differences stability reactivity derived from substrates described terms electronic stereochemical properties atoms.

[Structure: see text]. The synthesis and characterization of a series organochalcogen (Se, Te) compounds derived from benzyl alcohol 13 are described. the key precursor dichalcogenides 15, 22, 29 was achieved by ortho-lithiation route. Selenide 18 obtained reaction dilithiated derivative 14 with Se(dtc)2. Oxidation 15 22 H2O2 afforded corresponding cyclic ester derivatives 17 24, respectively. selenide affords spirocyclic compound 19. presence intramolecular interactions in has been proven...

Abstract The synthesis of some ebselen analogues and diaryl diselenides, which have amino acid functions as an intramolecularly coordinating group (Se⋅⋅⋅O) has been achieved by the DCC coupling procedure. reaction 2,2′‐diselanediylbis(5‐ tert ‐butylisophthalic acid) or activated ester tetrakis(2,5‐dioxopyrrolidin‐1‐yl) ‐ butylisophthalate) with different C‐protected acids (Gly, L ‐Phe, ‐Ala, ‐Trp) afforded corresponding analogues. used precursor diselenides found to undergo facile...

A series of novel low-valent organoselenium compounds stabilized by Se⋅⋅⋅N intramolecular interactions (such as the one in figure) were synthesized, characterized, and examined for nonbonding interactions. correlation between distance 77Se chemical shift is attempted.

A series of intramolecularly coordinated organochalcogen compounds incorporating the 8-(dimethylamino)-1-naphthyl and 2-[(dimethylamino)methyl]phenyl groups has been synthesized. All were synthesized using ortholithiation methodology. Insertion elemental selenium into Li−C bond RLi (6) (R = 8-(dimethylamino)-1-naphthyl) afforded lithium areneselenolate RSeLi (7). Oxidative workup 7 yielded yellow diselenide 8 in good yield. Reaction with a stoichiometric amount sulfuryl chloride gave...

Synthesis, structure and thiol peroxidase-like antioxidant activity of several diaryl diselenides having intramolecularly coordinating amino groups are described; the both tertiary redox-active ferrocenyl units show excellent peroxidase activity.

The reaction of meta-phenylene-bis(1-methyl-1H-imidazole-2(3H)-selone) with [Pd2(μ-Cl)2(2-C6H4CH2NMe2)2] in dry benzene and glacial acetic acid resulted the formation an unsymmetrical 5,6-membered C,C,Se-Pd(II) pincer complex through C-H bond activation extrusion one selenium. This is first example a wherein central Pd(II) simultaneously coordinated to selone N-heterocyclic carbene. chelated type [PdL2](2+)2[PF6](-) (L = bis(selone)) was isolated from bis(selone) [PdCl2(PhCN)2] NH4PF6....

The salt metathesis reaction of two equivalents 8-lithioquinoline (C₆H₆NLi) with HgBr₂ afforded bis(quinoline-8-yl)mercury, [(C₆H₆N)₂Hg].

A series of diaryl ditellurides with and without coordinating amino/imino groups are synthesized by using either the Grignard route or heteroatom-directed aromatic lithiation route. The chiral ditelluride (R),(R)-bis[2-(4-ethyl-2-oxazolinyl)phenyl] is in an enantiomerically pure form stereoselective ortho-lithiation. thiol peroxidase activity studied H2O2 as a substrate PhSH cosubstrate. initial rates for reduction catalyzed much higher than those corresponding diselenides. comparison...

Bis[(2-dimethylaminomethyl)phenyl] diselenide (RSe)2 was obtained by the organolithium route. It underwent facile reaction with stoichiometric amounts of bromine and iodine to give corresponding arylselenium halides RSeBr novel RSeI in which selenium is covalently bonded iodine. With an excess it gave tribromide RSeBr3 but a similar only RSeI. diazomethane selenoether (RSe)2CH2 HCl known bis(hydrochloride)(RSe)2·2HCl. A catalytic conversion alkenes into allylic acetates using carried out....

Enzyme mimicry: Halogenation of diselenide 1 affords the cyclic selenenate ester 2 (see scheme) through a highly unstable selenenic acid intermediate. Compound exhibits strong intramolecular nonbonding Se⋅⋅⋅O interaction. Both and show excellent glutathione peroxidase-like catalytic activity. Supporting information for this article is available on WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z460380_s.pdf or from author. Please note: The publisher not responsible content...

Abstract The synthesis and characterization of benzisochalcogenazolones (ebselen derivatives 16 − 21 ) is described. was achieved by treating the bromo precursors 11 13 with an appropriate dilithium dichalcogenide. benzisoselenazolones 18 also accomplished alternative route, that is, corresponding methoxymethyl selenides 22 23 1 equiv. bromine. lithiation followed treatment bis(methoxymethyl) diselenide. 17 were characterized single‐crystal X‐ray techniques. GPx‐like catalytic activities...

The reaction of [2-(2-phenyl-5,6-dihydro-4H-1,3-oxazinyl)]lithium (13), containing a six-membered oxazine ring, with elemental selenium gave lithium aryldiselenolate (14) as the major intermediate along other polyselenolates (15 and 16), whereas [2-(4,4-dimethyl-2-phenyloxazolinyl]lithium (21), five-membered oxazoline on only arlyselenolate 22 under similar conditions. unusual selenation aryllithium 13 has been studied by ES-MS spectrometry. oxidative workup in situ-generated...

Abstract The syntheses of the three selenenium cations 17 – 19 derived from N ‐[ n ‐butyl‐(3‐nitrobenzylimino)]phenyl selenide ( 14 ) are described. Precursor was synthesized by treating ‐(2‐bromo‐3‐nitrobenzylimino)benzene 12 with in situ generated BuSeNa. cation chloride as counteranion isolated when treated sulfuryl (SO 2 Cl presence triethylamine (Et 3 N). bromide 18 and tribromide counteranions, were Br Et N. Reaction thiophenol afforded two unexpected products: cyclic diselenide 20...

The isolation of pure [2-(phenylazo)phenyl-C,N′]tellurium(IV) tribromide (6) has been achieved by modifying the reported procedure, which involved transmetalation [2-(phenylazo)phenyl-C,N′]mercury(II) chloride (7) with TeBr4. mixed-valent derivative bis[2-(phenylazo)phenyl-C,N′]ditellurium dichloride (19), incorporating both a divalent and tetravalent tellurium, was obtained serendipitously during reduction trichloride (16) hydrazine hydrate. Bis[2-(phenylazo)phenyl-C,N′]telluride (10)...

Abstract The syntheses of selenenate/seleninate esters and related derivatives by aromatic nucleophilic substitution (S N Ar) reactions 2‐bromo‐3‐nitrobenzylalcohol ( 13 ) 2‐bromo‐3‐nitrobenzaldehyde 17 with Na 2 Se / n BuSeNa are described. reaction at room temperature afforded 7‐nitro‐1,2‐benzisoselenole(3 H) 15 instead the desired diaryl diselenide 14 . Oxidation selenenate ester hydrogen peroxide corresponding selenium(IV) derivative, selenium oxide 18 )....

Selones, since their first report in 1963, have attracted significant interest with respect to bonding, structure and more importantly as an ancillary ligand for complexation various met...