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• 109-04-6 2-bromo-pyridine 
• 14971-39-2 benzeneselenolate ion 

Relevant academic research and scientific papers

Relative Reactivities of Nucleophiles Derived from Group 6A toward Aryl Radicals

Competition experiments have been carried out in liquid ammonia at reflux temperature to determine the relative rate constants for the coupling reactions of nucleophiles derived from group 6A of the periodic table toward aryl radicals.The nucleophiles studied were of type PhZ- (Z=S, Se, Te).It has been proposed that these nucleophiles react under photochemical stimulation with haloaromatic substrates through the SRN1 mechanism of aromatic substitution.The experimental results suggest that the coupling reaction aryl radical-PhZ- anion can be reversible or irreversible depending on the nature of the aryl moiety and the PhZ- nucleophile.Relative rate constants have been determined under conditions of irreversible coupling of the nucleophiles PhZ- (Z=S, Se, Te) with 2-quinolyl radicals.Results here reported indicate an increasing reactivity as we go down the group: PhO- (0.0), PhS- (1.00), PhSe- (5.8), PhTe- (28).The relative rate constant when one of the coupling reactions is reversible supports our mechanistic suggestions.

A mechanistic study of the synthesis, single crystal X-ray data and anticarcinogenic potential of bis(2-pyridyl)selenides and -diselenides

The reaction of bis(organyl)diselenide with a reducing agent, such as LiAlH4, NaBH4, Li(C2H5)3BH, etc., generally leads to cleavage of the Se-Se bond resulting in the formation of the corresponding organylselenols/selenolates. However, this work for the first time demonstrates the scisson of the C(pyridine)-Se bond in bis(2-pyridyl)diselenides with LiAlH4. The reaction affords analytically pure bis(2-pyridyl)selenides in near quantitative yields. The reaction pathway involves the formation of a selenated aluminato complex followed by the scission of the C(pyridine)-Se bond and generation of LiAlSeH2. The generation of LiAlSeH2 was established by experimental and NMR analysis. The mechanism of the reaction has been supported by theoretical analysis. Single crystal X-ray structure determination of bis(3-methyl-2-pyridyl)selenide (2e) was performed and it shows that the molecules are self-assembled in a 2D-network of C-H?N hydrogen bonds and π?π stacking interactions. The synthesized compounds were also evaluated against the Raji cancer cell line (acute lymphoid leukemia).

Synthesis, characterization, structures and GPx mimicking activity of pyridyl and pyrimidyl based organoselenium compounds

Pyridyl and pyrimidyl based organoselenium compounds have been synthesized and characterized by analytical and spectroscopic techniques. Molecular structures of 2,2′-dipyrimidyl diselenide (1b), 2,2′-dipyrimidyl selenide (2b) and 2-pyrimidyl seleno ethanoic acid (3d) have been determined by single crystal X-ray diffraction analyses. The 3d is associated in the solid state through hydrogen bonding between carboxylic acid proton and N2 of the pyrimidyl ring of an adjacent molecule. The in vitro GPx-like catalytic activity for these compounds was evaluated by 1H NMR and HPLC methods where H2O2 was reduced by dithiothreitol (DTTred) and glutathione (GSH) as a thiol cofactor, respectively, in the presence of catalytic amounts of organoselenium compounds. The electron density around selenium atom (-SeSe- or -Se-) which is reflected by 77Se{ 1H} NMR chemical shifts, has been found to be one of the crucial factors in influencing their overall GPx like activity.

LITHIUM DISELENIDE IN APROTIC MEDIUM - A CONVENIENT REAGENT FOR SYNTHESIS OF ORGANIC DISELENIDES

The reduction of selenium with lithium in THF in the presence of diphenylacetylene as a catalyst afforded lithium diselenide, which reacted with electrophiles giving alkyl or aryl diselenides 1 - 3 and selenides 4, as by-products.The useful method for preparation of diselenides based on this reaction was elaborated.