It has been found that both eugenol and isoeugenol derivatives reacted with 2-pyridinesulfenyl and 2-pyridineselenenyl halides in a regioselective mode affording products with opposite regiochemistry. Synthesis of new families of 2H,3H-[1,3]thia- and -selenazolo[3,2-a]pyridin-4-ium heterocycles has been developed by annulation reactions of 2-pyridinechalcogenyl halides with natural compounds (eugenol, isoeugenol, methyl eugenol, methyl isoeugenol, acetyl eugenol, trans-anethole) and their structural analogs. The influence of the substrate structure and the nature of halogen on the product yields are studied. The 2-pyridinesulfenyl and 2-pyridineselenenyl chlorides are more efficient reagents compared to corresponding bromides. The obtained condensed heterocycles are novel water-soluble functionalized compounds with promising biological activity.

The regioselective synthesis of novel functionalized condensed organochalcogen compounds by chalcogenocyclofunctionalization reactions based on chalcogen halides and the natural products thymol and carvacrol has been developed. The reactions of selenium dibromide with allyl thymol and allyl carvacrol proceeded in methylene chloride at room temperature in the presence of NaHCO₃ affording bis[(7-isopropyl-4-methyl-2,3-dihydro-1-benzofuran-2-yl)methyl] and bis[(4-isopropyl-7-methyl-2,3-dihydro-1-benzofuran-2-yl)methyl] selenides in 90–92% yield. Similar sulfides were obtained in 70–72% yields by the reaction of sulfur dichloride in chloroform under reflux. Trihalotellanes containing the same organic moieties were synthesized from allyl thymol, allyl carvacrol and tellurium tetrachloride or tetrabromide in quantitative yields. Corresponding functionalized ditellurides were prepared in 91–92% yields by the reduction of the trichlorotellanes with sodium metabisulfite in two-phase solvent system. The comparison of reactivity of sulfur, selenium and tellurium halides in chalcogenocyclofunctionalization and distinguishing features of each reaction were discussed.

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 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.

The capability of thallium(I) alkylenedithiocarbamates to bind gold(III) from solutions in 2 M HCl was studied. Double complexes [Au{S₂CN(CH₂)₅}₂][TlCl₄] and [Au{S₂CN(CH₂)₆}₂][TlCl₄] were preparatively isolated as individual forms of gold(III) fixation to the solid phase. In the crystalline state, the ionic structural units of the complexes are combined together by the secondary Au···S, Tl···S, and S···Cl bonds that results in complicated supramolecular architectures. Thermal behavior of the compounds was studied using the simultaneous thermal analysis technique; reduced elemental gold and thallium(I) chloride were identified as the final thermolysis products.

Introduction: A simple method for the preparation of 5-(trifluoroacetyl)imidazoles was elaborated. Method: The reaction of trifluoromethyl(-bromoalkenyl)ketones with benzimidamides was employed to afford the target heterocycles in good yields. Result: The assembly of imidazole core proceeds via aza-Michael adduct formation followed by intramolecular nucleophilic substitution and spontaneous aromatization as an oxidation sequence. Conclusion: The yields of target imidazoles can be improved by the use of soft oxidizing agents.