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The reaction of (–)-cytisine with 2-(chloroselanyl)pyridine-1-oxide afforded the corresponding selenenylamide. Its biological activity against Aspergillus oryzae micromycetes was revealed.

Cadmium (C20H16Cd2N4O4Se4) (I) and nickel (C10H8N2NiO2Se2) (II) selenolates are synthesized by the exchange reactions of sodium 1-oxypyridyl-2-selenolate and cadmium(II) and nickel(II) chlorides. The molecular and crystal structures of the complexes are determined by X-ray structure analysis (CIF files CCDC nos. 1585246 (I) and 1585251 (II)). Complex I forms a centrosymmetric dimer in which the coordination polyhedron of the cadmium atom is a distorted trigonal bipyramid and the selenium atoms take the trans configuration. Complex II containing the solvate C2H5OH molecule has a square structure and is a monomer. Unlike complex I, in complex II the selenium atoms of the ligands take the cis configuration. The crystal packings in complexes I and II are formed by weak intermolecular hydrogen bonds C–H···O and C–H···Se.

We implemented genome-wide expression profiling to identify the mechanisms of toxicity of an organoselenium compound bis(2-pyridine-1-oxide) diselenide to the fungus А. oryzae RIB40. We uncovered changes in the expression levels in 72 genes. In particular, we observed a downregulation in the levels of several copper ion transmembrane transporter genes. In turn, we found a significant upregulation in the genes encoding oxidoreductases. The latter results are supported by biochemical experiments that revealed an increase in oxidoreductase activity in response to bis(2-pyridine-1-oxide) diselenide treatment. The results of a large-scale microarray analysis of the А. oryzae RIB 40 were confirmed by real-time quantitative PCR.

A reaction of dimethyl bicyclo[2.2.2]oct-5-ene-endo-2,endo-3-dicarboxylate with 1,3-benzо- thiazole-2- and 3-methoxycarbonylpyridine-2-sulfenyl chlorides leads to two types of heterocyclization products, which are formed through the ring closure by the oxygen atom of the carbоmethoxy group and/or by the nitrogen atom of the hetaryl fragment of the sulfenylating agent. The product ratio is affected by the medium nature and structural features of sulfenyl chlorides.

Novel S- and Se-containing terpenoids were prepared by reacting (+)-camphene with N-heterocyclic selenyland sulfenyl chlorides.

New menthane-type derivatives were prepared via hetarylsulfenyl-chlorination reactions of (+)-carvone with 2-benzothiazolyl-, 4,6-dimethyl-2-pyrimidyl-, and 3-methoxycarbonyl-2-pyridylsulfenyl chlorides and 2-pyridylselenyl chloride.

Bis(4,6-dimethylpyrimidin-2-yl) diselenide, a new representative of dihetaryl diselenides, was obtained by successively treating selenourea with hydrochloric acid, acetylacetone, potassium hydroxide, and the system iodine—potassium iodide. The unusual planar trans-conformation of this compound (X-ray diffraction data) is stabilized by intramolecular attractive nonvalent Se…N interactions (Se…N, 2.926(1) A) and stacking of the π-systems of the aromatic heterocycles (the centers of the pyrimidine rings are spaced apart at 3.365(2) A). The energy parameters of the factors that make the molecular structure flattened were estimated by quantum chemical DFT calculations.

A reaction of 2-chloro-4,6-dimethylpyrimidine with sodium ditelluride in DMF afforded bis(4,6-dimethylpyrimidin-2-yl) ditelluride, a new representative of dihetaryl ditellurides. An X-ray diffraction study revealed an unusual planar trans-conformation of this compound, which is stabilized by both intramolecular attractive non-valent Te...N interactions (3.082(2) A) and π-stacking of the aromatic heterocycles (the centers of the pyrimidine rings are disposed at 3.421(3) ). The energy parameters of the factors that make the molecular structure flattened were estimated by quantum chemical DFT calculations.

The interaction of norbornene with the di(2-pyridyl) ditelluride–antimony pentachloride system in methylene chloride proceeds with the formation of exo-9-telluro-3-azoniatetracyclo-[9.2.1.02.10.03,8]tetradeca-3(8),4,6-triene chloroantimonates(III), which are the products of polar cycloaddition of tellurium-containing electrophiles at the multiple bond. The structure of the heterocyclization products was established by X-ray structural analysis.

Sulfenylating reagents have been obtained by the action of sulfuryl chloride or antimony pentachloride on di(2-pyridyl) disulfide. Their interaction with alkenes proceeds as addition-cyclization with ring closure by the nitrogen atom of the pyridine fragment of the sulfur-containing electrophile with the formation of 2,3-dihydro[1,3]thiazolo[3,2-a]pyridinium derivatives.

Cycloalkenes react with di(2-pyridyl) diselenide in the presence of antimony pentachloride with the formation of products of the selenenylating electrophile cycloaddition at the multiple bond. The final products of heterocyclization, chloroantimonates(III) of 2,3-dihydro[1,3]selenazolo[3,2-a]pyridinium derivatives were isolated.

The reaction of pyridine-2-selanyl chloride with alkenes and dienes gives 2,3-dihydro[1,3]selenazolo- [3,2-a]pyridinium derivatives as addition-cyclization products involving closure of the ring at the pyridine nitrogen atom of the selanylating electrophile.

The action of 2-pyridinetellurenyl chloride on alkenes results in the polar cycloaddition of the tellurium-centered electrophile at the multiple bond with the formation of 2,3-dihydro[1,3]tellurazolo[3,2-a]pyridinium derivatives.

A reaction of styrene with the di(2-pyridyl) diselenide—antimony pentachloride system furnishes 2,3-dihydro[1,3]selenazolo[3,2-a]pyridinium chloroantimonates(III) and (V), the products of cycloaddition of the selenylating agent at the multiple bond.

Reaction of perfluoro-1-ethyl-2-methyl-1-propenyliminochloromethanesulfenyl chloride with 1-allyl-2-methoxybenzene in methylene chloride and nitromethane gives as the main products β-and β-chloro sulfides plus derivative of 2,3-dihydrobenzofuran. The reaction in nitromethane in the presence of lithium perchlorate gave a product of addition of sulfur-containing electrophiles to the double bond-a derivative of 1,3-thiazolidin-2-one-in preference to the cycloaddition product.

Products of additive cyclization with ring closure at the nitrogen atom of the thiohetaryl unit were synthesized by the interaction of 4,6-dimethylpyrimidine-2-, 3-cyano-4,6-dimethylpyridine-2-, quinoline-8-, and 1,3-benzothiazole-2-sulfenyl chlorides with 3,3-dimethyl-1-butene.

2,3-Dihydrothiazolo[3,2-d]tetrazolium perchlorates have been synthesized by the interaction of 1-phenyl-5-tetrazolesulfenyl chloride with styrene and with (E)-1-phenylpropene in nitromethane in the presence of lithium perchlorate.

The structure of pyridine-2-tellurenyl chloride, the chlorination product of di(2-pyridyl) ditelluride by sulfuryl chloride, was studied by X-ray diffraction analysis.

Cycloaddition of 1,3-benzothiazole-2-selenenyl chloride to alkenes leads to 2,3-dihydrobenzo[d][1,3]selenazolo[2,3-b][1,3]thiazolium-4 derivatives.

One of the current methods of synthesis of unsaturated heterocycles is the electrophilic cyclization of alkynes under the action of different electrophiles, including sulfenyl and selanyl chlorides, with ring closure via the nucleophilic participation of the heteroatom of the functional group in the starting unsaturated compound [1]. With the aim of developing another variant of cyclizations in the AdE reactions of unsaturated compounds (which includes ring closure with nucleophilic participation of a heteroatom found in the structure of the starting electrophile) we have studied the reaction of 1,3-benzothiazole-2-sulfenyl chloride (1a) or 1,3-benzothiazole-2-selanyl chloride (1b) with p-methoxyphenylacetylene (2). We have previously shown that the reactions of the hetarenechalcogenyl chlorides 1a,b with alkenes form the products of cycloaddition at the double bond, i.e. the 2H,3H-benzo[d][1,3]thi(selen)azolo[2,3-b][1,3]thiazol-4-ium salts [2-4]. At the same time, it has been shown that the reactions of hetarenesulfenyl chlorides (including compound 1a) with diphenylacetylene in methylene chloride gives only -chlorovinyl sulfides [5] as products of 1,2-addition. In the present work, we have used compound 2 as a model alkyne containing a p-methoxy substituent as a powerful electron donor in order to stimulate novel reaction routes.

Cycloalkenes react with di(2-pyridyl) diselenide in the presence of antimony pentachloride with the formation of products of the selenenylating electrophile cycloaddition at the multiple bond. The final products of heterocyclization, chloroantimonates(III) of 2,3-dihydro[1,3]selenazolo[3,2-a]pyridinium derivatives were isolated.

A reaction of styrene with the di(2-pyridyl) diselenide—antimony pentachloride system furnishes 2,3-dihydro[1,3]selenazolo[3,2-a]pyridinium chloroantimonates(III) and (V), the products of cycloaddition of the selenylating agent at the multiple bond.

The novel fused selenazole heterocycles (V) and (VII) are formed both diastereo- and regioselectively.

A reaction of 2-pyridinetellurium trichloride with unsaturated hydrocarbons leads to [1,3]tellurazolo[3,2-a]pyridinium-4 derivatives — the products of polar cycloaddition of tellurium-containing electrophile at the multiple bond.

One of the current methods of synthesis of unsaturated heterocycles is the electrophilic cyclization of alkynes under the action of different electrophiles, including sulfenyl and selanyl chlorides, with ring closure via the nucleophilic participation of the heteroatom of the functional group in the starting unsaturated compound [1]. With the aim of developing another variant of cyclizations in the AdE reactions of unsaturated compounds (which includes ring closure with nucleophilic participation of a heteroatom found in the structure of the starting electrophile) we have studied the reaction of 1,3-benzothiazole-2-sulfenyl chloride (1a) or 1,3-benzothiazole-2-selanyl chloride (1b) with p-methoxyphenylacetylene (2). We have previously shown that the reactions of the hetarenechalcogenyl chlorides 1a,b with alkenes form the products of cycloaddition at the double bond, i.e. the 2H,3H-benzo[d][1,3]thi(selen)azolo[2,3-b][1,3]thiazol-4-ium salts [2-4]. At the same time, it has been shown that the reactions of hetarenesulfenyl chlorides (including compound 1a) with diphenylacetylene in methylene chloride gives only -chlorovinyl sulfides [5] as products of 1,2-addition. In the present work, we have used compound 2 as a model alkyne containing a p-methoxy substituent as a powerful electron donor in order to stimulate novel reaction routes.

Cycloaddition of 1,3-benzothiazole-2-selenenyl chloride to alkenes leads to 2,3-dihydrobenzo[d][1,3]selenazolo[2,3-b][1,3]thiazolium-4 derivatives.

In previous work [1–3], we synthesized a number of 2,3-dihydro[1,4]thiazino[2,3,4-ij]quinolinium-4 derivatives by the reaction of 8-quinolinesulfenyl chloride with alkenes. 8-Quinolineselanyl chloride (1) was obtained in a study of the feasibility of using this method for the synthesis of analogous selenium-nitrogencontaining heterocycles. The reactions of chloride 1 with indene 2 and styrene 3 were investigated. The reaction of selanyl chloride 1 with unsaturated compounds 2 and 3 in methylene chloride at 20°C leads to peri-fused systems 4 and 5 in 91 and 82% yield, respectively. H NMR spectroscopy showed that these reactions proceed regioand stereospecifically.