Maxim V. Musalov

A previously unknown family of 9-selenabicyclo[4.2.1]nonane derivatives was obtained in up to 98% yields by the transannular addition reaction of selenium dihalides with 1,3-cyclooctadiene. Conditions for selective anti,anti and syn,anti ( endo–exo diastereomer) additions to obtain the endo–endo or endo–exo diastereomers, respectively, were found. An approach to selectively introducing two target substituents into selenabicyclo[4.2.1]nonane, including isomerization of the endo–exo diastereomer into the endo–endo derivative, was developed.

The regio- and stereoselective synthesis of new ( Z )-selenocyanatoacrylamides containing N -alkylamide groups and cyclic amide substituents (yields 76–93%) by the reaction of potassium selenocyanate with 3-trimethylsilyl-2-propynamides was developed. The reaction proceeded in aqueous acetonitrile in the presence of ammonium chloride and was accompanied by a desilylation process.

The transannular addition reaction of selenium dichloride and dibromide to 1,3- cyclooctadiene was carried out for the first time. Based on this reaction, regio- and stereoselective approaches to new 2,3- bifunctional derivatives of 9- selenabicyclo[4.2.1]nonane with endo- exo and endo- endo stereochemistry have been developed. Conditions for stereoselective transannular anti, syn- and anti, anti- addition reactions have been found. A method for the sequential introduction of two different functional groups into the 9- selenabicyclo[4.2.1]nonane structure has been developed.

A regio- and stereoselective synthesis of new vinyl selenocyanates (yields 76–93 %), containing N-alkylamide groups and heterocyclic amide substituents, has been developed based on the reaction of 3-trimethylsilyl-2-propynamides with potassium selenocyanate. The reaction proceeds in the presence of ammonium chloride in aqueous acetonitrile and is accompanied by a desilylation process.

The Special Issue “New Chemo-, Regio- and Stereoselective Reactions and Methods in Organic Synthesis” collects eight articles that have developed advanced approaches to the chemo-, regio- and stereoselective synthesis of novel important compounds, scaffolds, synthons, and practically valuable products

The review examines recent advances in the design and synthesis of 1,3-selenazole derivatives since 2000. Various synthetic approaches to 1,3-selenazoles and reaction conditions are discussed. The beneficial properties of 1,3-selenazoles, especially their biological activity, are emphasized. Compounds with antitumor, antiviral (HIV-1 and HIV-2), antibacterial, antifungal, antiproliferative, anticonvulsant, and antioxidant activity are highlighted.

A convenient synthesis of a novel fluoroquinolone precursor, methyl 6,7-difluoro-2-[(4-fluorobenzyl)sulfanyl]-4-hydroxyquinoline-3-carboxylate, at a 78% yield starting from 3,4-difluorophenyl isothiocyanate was developed. The structure of the product was established by ¹H, ¹³C, and ¹⁹F NMR spectroscopy, mass spectrometry, IR spectroscopy and confirmed by elemental analysis. The title compound, containing the pharmacophoric 4-fluorobenzyl group, will be used in the synthesis of novel fluoroquinolone derivatives.

One of the important directions for increasing the immunogenic properties of vaccine strains against highly dangerous infections is the search for adjuvants that not only stimulate the immunological effectiveness of vaccination, but can also provide a metabolic correction of the vaccination process. Organoselenium compounds have immunotropic properties and an antioxidant effect, and therefore, the study of the effect of the organoselenium compound 2,6-dipyridinium-9-selenabicyclo[3.3.1]nonane dibromide (974zh) on the activity of the TLR2 and TLR4 gene expression by macroorganism cells of experimental animals immunized with Yersinia pestis EV NIIEG vaccine strain, is a current area of research.The aim of the work. To assess the TLR2 and TLR4 gene expression by cells of the immune phagocyte system of experimental animals immunized with the Y. pestis EV vaccine strain against the background of immunomodulation with the organoselenium compound 974zh.Materials and methods. The study was carried out on 125 certified outbred white mice. Biological material (blood, spleen) was disinfected, and the spleen was homogenized. RNA isolation and reverse transcription were performed using commercial reagent kits. The expression level of the TLR2 and TLR4 genes was determined using real-time polymerase chain reaction with specific primers.Results. When assessing innate immunity using the example of blood and spleen cells of animal models, features of the TLR2 and TLR4 gene expression were revealed in response to the introduction of the Y. pestis EV vaccine strain against the background of immunomodulation with the 974zh. It was found that 974zh induces a statistically significant increase in TLR2 gene expression when co-administered with Y. pestis EV at a dose of both 104 CFU and 103 CFU.Conclusion. Y. pestis EV against the background of immunomodulation with 974zh, stimulates the expression of the TLR2 and TLR4 genes, which may indicate an increase in the immunogenic properties of the Y. pestis EV vaccine strain under the influence of this preparation.

Highly efficient and convenient methods for the preparation of 35 novel derivatives of 9-selenabicyclo[3.3.1]nonane and 9-selenabicyclo[3.3.1]nonene-2 in high yields based on the adduct of the transannular addition of SeBr₂ to 1,5-cyclooctadiene were developed. The methods for the amination of the adduct made it possible to obtain both diamino selenabicyclo[3.3.1]nonane derivatives and their dihydrobromide salts in one step in 88–98% yields. The methods meet the criteria of click chemistry. Compounds with high glutathione peroxidase mimetic activity were found among water-soluble dihydrobromide salts. The selective reaction of 2,6-dibromo-9-selenabicyclo[3.3.1]nonane with acetonitrile to form 6-bromo-9-selenabicyclo[3.3.1]nonene-2 was discovered. The latter compound served as a promising starting material to give rise to the new class of selenabicyclo[3.3.1]nonene-2 derivatives, e.g., 6-alkoxy-9-selenabicyclo[3.3.1]nonenes were obtained in 94–99% yields.