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A number of highly efficient methods for the preparation of novel derivatives of 9-selenabicyclo[3.3.1]nonane in high yields based on selenium dibromide and cis,cis-1,5-cyclooctadiene are reported. The one-pot syntheses of 2,6-diorganyloxy-9-selenabicyclo[3.3.1]nonanes using various O-nucleophiles including alkanols, phenols, benzyl, allyl, and propargyl alcohols were developed. New 2,6-bis(1,2,3-triazol-1-yl)-9-selenabicyclo[3.3.1]nonanes were obtained by the copper-catalyzed 1,3-dipolar cycloaddition of 2,6-diazido-9-selenabicyclo[3.3.1]nonane with unsubstituted gaseous acetylene and propargyl alcohol. The synthesis of 2,6-bis(vinylsulfanyl)-9-selenabicyclo[3.3.1]nonane, based on the generation of corresponding dithiolate anion from bis[amino(iminio)methylsulfanyl]-9-selenabicyclo[3.3.1]nonane dibromide, followed by the nucleophilic addition of the dithiolate anion to unsubstituted acetylene, was developed. The glutathione peroxidase-like activity of the obtained water-soluble products was estimated and compounds with high activity were found. Overall, 2,6-Diazido-9-selenabicyclo[3.3.1]nonane exhibits the highest activity among the obtained compounds.

Highly efficient stereoselective syntheses of novel bis( E -2-chlorovinyl) selenides and bis( E -2-bromovinyl) selenides in quantitative yields by reactions of selenium dichloride and dibromide with alkynes were developed. The reactions proceeded at room temperature as anti -addition giving products exclusively with ( E )-stereochemistry. The glutathione peroxidase-like activity of the obtained products was estimated and compounds with high activity were found. The influence of substituents in the products on their glutathione peroxidase-like activity was discussed.

The efficient regio- and stereoselective synthesis of ( Z , Z )-3,3'-selanediylbis(2-propenamides) in 76-93% yields was developed based on the reaction of sodium selenide with 3-trimethylsilyl-2-propynamides. ( Z , Z )-3,3'-Selanediylbis(2-propenamides) are a novel class of organoselenium compounds. To date, not a single representative of 3,3'-selanediylbis(2-propenamides) has been described in the literature. Studying glutathione peroxidase-like properties by a model reaction showed that the activity of the obtained products significantly varies depending on the organic moieties in the amide group. Divinyl selenide, which contains two lipophilic cyclohexyl substituents in the amide group, exhibits very high glutathione peroxidase-like activity and this compound is considerably superior to other products in this respect.

The last decade has witnessed significant progress in the development of novel synthetic methods for the preparation of a variety of new functionalized and condensed compounds via reactions of organic dichalcogenides with acetylenic derivatives. The present review highlights recent developments in the synthesis of organoselenium compounds based on the reactions of organic diselenides with acetylenes over the past few years. The discussion mainly focuses on the literature data for the last 5 years. It is worth noting that the lion's share of this material is devoted to catalytic and electrophile-mediated reactions with aromatic compounds, containing a triple bond and nucleophilic functional groups. [ABSTRACT FROM AUTHOR]

Oxidative stress is the cause of various pathologies and disorders of cellular functions. Substances that reduce the pathological effect of oxidative stress on homeostasis include organoselenium compounds of natural and synthetic origin. Depending on the structure, organoselenium compounds can exhibit different biological activities, for example, reducing oxidative stress, participating in the regulation of signaling systems, influencing the synthesis of cytokines, etc. This makes them promising products for the development of new means of metabolic correction and drugs with enzyme-like activity. This study is aimed at developing an effective method for the synthesis of functional organoselenium compounds and studying their antioxidant effect in vivo under stress conditions. A one-pot catalyst-free method of transannular addition-functionalization of cis,cis-1,5-cyclooctadiene with selenium dihalides in the presence of nucleophiles was developed. For the first time, the antioxidant activity of functionalized 9-selenabicyclo[3.3.1]nonanes was studied in vivo. Quantitative characteristics of the effect on the level of lipid peroxidation and the activity of glutathione peroxidase and glutathione reductase under stress conditions were obtained. The effect of substituents in the selenium-containing scaffold on the biological activity of the compounds was studied. The water-soluble 9-selenabicyclo[3.3.1]nonane derivatives, containing hydroxyl and 2-hydroxyethoxy groups, which increased the activity of both glutathione peroxidase and glutathione reductase, were discovered. [ABSTRACT FROM AUTHOR]

The one-pot efficient synthesis of novel functionalized organoselenium compound by bis-alkoxyselenenylation of alkenes with selenium dibromide and alcohols was developed. The reaction of the selenium dibromide with cyclopentene or cyclohexene in the system alcohol/sodium bicarbonate/methylene chloride at room temperature afforded bis(2-alkoxycycloalkyl) selenides in 90–99% yields. The regioselective and efficient method for bis-alkoxylation of terminal alkenes was developed based on the addition of selenium dibromide with 1-alkenes in acetonitrile followed by refluxing of addition products in alcohols in the presence of traces of sulfuric acid. This method made it possible to selectively obtain bis(2-alkoxyalkyl) selenides in 94–98% yields. [ABSTRACT FROM AUTHOR]

Abstract: The reactions of selenium dichloride and dibromide with divinyl sulfone leading to novel selenium heterocycles, 2,4-bis(halomethyl)-1,3-thiaselenetane-1,1-diones and 5-halo-2-halomethyl-1,3-thiaselenolane-1,1-diones, have been studied. Under the action of silica gel or pyridine, 5-halo-2-halomethyl-1,3-thiaselenolane-1,1-diones undergo facile regioselective dehydrohalogenation into 5-halo-2-methylene-1,3-thiaselenolane-1,1-diones. [Copyright &y& Elsevier]