Homolytic telomerization of vinyltrimethylsilane with 5,5-dimethyl-1,3-dioxane

The homolytic telomerization of vinyltrimethylsilane by 5,5-dimethyl-1,3-dioxane follows three principal routes, with the formation of 2- and 4-substituted 5,5-dimethyl-1, 3-dioxanes and a formate ester. The rings in the reaction products (2-trimethylsilylethyl- and 4-trimethylsilylethyl-5,5-dimethyl-1,3-dioxane) exist in the chair conformation. The substituants in the 2- and 4-positions of the dioxane ring occupy equatorial positions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1031–1035, August, 1986.     

Influence of the breakdown mechanism on the behavior of lead-antimony alloys with an alternating load

For the example of Pb-Sb alloys, the influence of aging is investigated, as a function of its mechanism, on the resistance to fatigue deformation, leading to rupture along the grain boundaries. It is shown that continuous breakdown increases the cyclic life, whereas discontinuous breakdown considerably reduces it. The most effective means of suppressing discontinuous breakdown, and hence increasing the resistance to grain-boundary fatigue breakdown, is by doping with elements which reduce the mobility of the grain boundaries, such as tellurium in led. Doping with elements that facilitate discontinuous breakdown (such as As in PbSb) leads to significant reduction in the fatigue resistance.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 61–64, August, 1982.     

Kinetics of oxidation of dioxanes by ozone in aqueous solutions

The kinetics of oxidation of dioxanes by ozone was investigated by a spectrophotometric method in the temperature interval of 281-311 K. The activation parameters of the reaction were determined.     

Synthesis and Stereochemistry of Substituted 1,3-Dioxa-2-silacyclohexanes: VII. Synthesis and Stereochemistry of Substituted 2-Vinyl-2-methyl-1,3-dioxa-2-silacyclohexanes

The stereochemistry of substituted 2-vinyl-2-methyl-1,3-dioxa-2-silacyclohexanes was studied by ^1Hand ^13C NMR spectroscopy. The configurational and conformational assignment of a mixture of 2-vinyl-2,4-dimethyl-1,3-dioxa-2-silacyclohexane diastereomers with various ratios of the cis and trans forms was made. The molecules of both conformers occur chiefly in the chair conformartion with equatorial location of the methyl group at the C⁴ atom. The experimental data were confirmed by AM1 and MM+ optimization of the molecular geometry.     

Synthesis and transformations of 4-acrylamido-4-methyltetrahydropyran

4-Acrylamido-4-methyltetrahydropyran was obtained via the Ritter reaction on the basis of cyclic unsaturated ethers and acrylonitrile. This amide is not hydrolyzed in alkaline media but does add dichlorocarbene and bromine to the double bond. Dehydrobromination of the dibromo derivative leads to the corresponding amide with a triple bond.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 461–462, April, 1985.     

Radical reactions of vinyltrimethylsilane with 2-methyl-1,3-dioxolane

Conclusions Vinyltrimethylsilane in radical reactions with a cyclic acetal gives 2- and 4-substituted 1,3-dioxolanes together with telomers of linear structure. Increasing the concentration of the monomer and reducing the reaction temperature favors an increase in the proportion of cyclic telomers.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1616–1620, July, 1986.     

Radical addition of 2-trichloromethyl-1,3-dioxolane to vinyltrimethylsilane

Conclusion The addition of 2-trichloromethyl-l,3-dioxolane to vinyltrimethylsilane upon initiation by a system consisting of Fe(CO)₅ and a nucleophilic cocatalyst proceeds to cleavage of a C-Cl bond in the trichloromethyl group with the formation of an adduct containing the dioxolanyl ring.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2351–2353, October, 1986.