A novel methodology for accelerating the annulation was developed based on the reactions of selenium dihalides in the presence of alcohols.

<p class="Default"><strong> </strong></p><p class="Default">The effect of 2,6-dipyridinium selenabicyclo[3.3.1]nonandibromide (996 zh) on the level of lipid peroxidation (LPO), on the activity of glutathione reductase (GR) and on the morphometric parameters of oilseed radish seedlings under normal conditions and under stress (200 mmol NaCl) has been studied. It has been established that the substance 996 zh at a concentration of 100 μm exerted an antioxidant effect reducing the level of lipid peroxidation and increasing the activity of GR. In connection with that the germinating ability of seeds and the biomass of the roots and stems of seedlings increased, both under normal conditions and under stress conditions.</p><p class="Default">The concentration of the substance 996 zh of 1000 μmol had a toxic effect, increasing the LPO level in normal conditions, but neutralized the effect of stress due to the addition of NaCl. This concentration had a slight inhibitory effect on germinability and on root development in seedlings. However, the same concentration of the substance 996 zh (1000 μmol) had a positive effect on the development of shoots under both normal and stressed conditions.</p>

The original goal of this research was to study stereochemistry of selenium dihalides addition to cycloalkenes and properties of obtained products. Remarkable alkene-to-alkene and alkene-to-alkyne transfer reactions of selenium dibromide and PhSeBr were discovered during this research. The adducts of selenium dibromide with alkenes or cycloalkenes easily exchange SeBr2 with other unsaturated compounds, including acetylenes, at room temperature, in acetonitrile. Similar alkene-to-alkene and alkene-to-alkyne transfer reactions of the PhSeBr adducts with alkenes or cycloalkenes take place. The supposed reaction pathway includes the selenium group transfer from seleniranium species to alkenes or alkynes. It was found that the efficient SeBr2 and PhSeBr transfer reagents are Se(CH2CH2Br)2 and PhSeCH2CH2Br, which liberate ethylene, leading to a shift in equilibrium. The regioselective and stereoselective synthesis of bis(E-2-bromovinyl) selenides and unsymmetrical E-2-bromovinyl selenides was developed based on the SeBr2 and PhSeBr transfer reactions which proceeded with higher selectivity compared to analogous addition reactions of SeBr2 and PhSeBr to alkynes under the same conditions.