The catalytic reactions of triethyl- and triethoxy-silane with unsaturated sulphides

The hydrosilylation of mono- and di-alkenyl sulphides of the type RS(CH₂)_nCH=CH₂ (R = C₂H₅, CH₂=CH, CH₂=CHCH₂, C₃H₇, n = 0, 1 and 4) by triethyl- and triethoxy-silane, catalyzed by H₂PtCl₆·6 H₂O, (Ph₃P)₃RhCl and (PhCN)₂PdCl₂·Ph₃P, has been studied. The addition of hydrosilane to the double bond of alkenyl sulphide leads to a mixture of two isomeric monoadducts. The hydrosilane can cleave the C---S bond of the initial sulphides giving the corresponding derivatives of thiosilanes, X₃SiS(CH₂)_nCH=CH₂ (X = C₂H₅, C₂H₅O). Hydrosilylation of alkenyl sulphides is accompanied by some side reactions such as dehydrocondensation, reduction and polymerization. The effect of the catalyst nature, the structure of hydrosilane and alkenyl sulphide on the reaction route has been investigated.     

Structure,tautomerism, and transformations of β-(3-nitro-2-pyridyl)- and β-(3-nitro-4-pyridyl)pyruvic acid esters

It was shown by means of IR, UV, and PMR spectra that -(3-nitro-2-pyridyl)pyruvic acid esters are practically completely enolized in the crystal state and in solution; ethyl -(3-nitro-4-pyridyl)pyruvate has an enol structure in the crystalline state and in pyridine solution but exists as a mixture of keto and enol forms in low-polarity solvents.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 389–393, March, 1974.     

Convergence of series with respect to generalized Haar systems

. . . . , L _p[0, l], 1 >p <, .     

Synthesis and properties of low-molecular-weight copolymers of acrylamide with 2-acrylamido-2-methylpropanesulfonic acid,as potential drug carriers

Nontoxic water-soluble low-molecular-weight (MW 14 000–36 000 Da) copolymers of acrylamide with 2-acrylamido-2-methylpropanesulfonic acid, containing from 17.3 to 37.6 mol % sulfonate-containing monomeric units, were synthesized by heterophase radical polymerization in isopropanol or ethanol at 50°C with azobis(isobutyronitrile) as an initiator. Original Russian Text M.V. Solovskii, M.Yu. Eropkin, E.M. Eropkina, A.V. Slita, M.Yu. Smirnova, E.N. Vlasova, E.B. Tarabukina, A.I. Amirova, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 10, pp. 1674–1678.     

Clathrate formation and phase transitions in β-hydroquinone

Clathrate thermodynamic stability conditions and the phase transitions associated with either the orientational ordering of the guest molecules or with the condensation of the guest molecules in the host lattice are investigated by means of the common microscopic model. The theory proposed describes the thermodynamic properties of -hydroquinone (Q ) clathrates. The dielectric constant (T) was measured experimentally inQ ·CH₃OH andQ ·SO₂ in the temperature range from 4.2 to 300 K and the phase transitions were found. It is shown that the theory qualitatively explains the experimental data obtained.Dedicated to Professor H. M. Powell.     

Pyrylia[2,3-d]pyrimidine salts

The condensation of 2-amino- and 2-methylthio-4, 6-dihydroxypyrimidines and barbituric and thiobarbituric acids with -diketones in strong acids leads to pyrylia[2,3-d]pyrimidine salts, which on treatment with ammonia or aniline are converted to pyrido[2,3-d]pyrimidines or to 8-phenylpyrido[2,3-d]pyrimidinium salts, respectively.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1484–1486, November, 1977.     

N,N′-Bis(trimethylsilylmethyl)thiocarbamide and N,N′-Bis(trimethylsilylmethyl)-λ6-thiocarbamide S,S-Dioxide

N,N′-Bis(trimethylsilylmethyl)-λ⁶-thiocarbamide S,S-dioxide was synthesized by oxidation of N,N′-bis(trimethylsilylmethyl)thiocarbamide with hydrogen peroxide. The synthesized dioxide is a less active reducing agent than previously studied S,S-dioxides of organosilicon thiocarbamides in which the silicon atom is separated from the thiocarbamide fragment by a -CH₂CH₂CH₂- bridge.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 912–914.Original Russian Text Copyright © 2005 by Vlasova, Grigor’eva, Voronkov.     

Organosilicon compounds containing carbofunctional biguanidine group

The reaction of triethoxysilylpropylamine (AGM-9) with dicyanodiamide was studied. The condensation of AGM-9 with dicyanodiamide occurs in the presence of a catalytic amount of CuCl₂ at 125–145°C within 5–24 h; it involves both the amino group of AGM-9 and ethoxy substituents at the Si atoms, with an unusual exchange of a Si-O bond for a Si-N bond. The final reaction product is 1-N-(3-triethoxysilylpropyl)-2-N-[3-aminopropylsilyl(diethoxy)]biguanidine. Its hydrolytic polycondensation yields an organosilicon polymer, a polycondensate of AGM-9 with 1-N-(3-triethoxysilylpropyl)biguanidine, which is a highly efficient sorbent for Ag(I) (static sorption capacity 544 mg g^?1).     

Reaction of γ-nitroketones and methyl 4-nitrobutanoates with formaldehyde and primary amines

5-Nitropentan-2-one reacts with methylamine and formaldehyde according to the Mannich reaction pattern to give 5-hexahydropyrimidinylcarbonyl-substituted 1-nitro-3,7-diazabicyclo[3.3.1]nonane in one experimental stage. When methyl 3-R-4-nitrobutanoates are used, the reaction stops after the formation of substituted 5-nitrohexahydropyrimidines in 40–98% yields. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1687–1693, July, 2005.