4,4-Dimethyl-4-silathiane-1-N-(trifluoromethanesulfonyl)-sulfimide,the first representative of the SiS-cycles triflamide derivatives

Russian Journal of General Chemistry -     

(<Emphasis Type="Italic">N</Emphasis>-trifluoromethanesulfonyl)sulfimides of linear and cyclic organosilicon sulfides

The reaction of sodium salt of N-(chloro)trifluoromethanesulfonamide with linear and cyclic fiveand six-membered organosilicon sulfides was studied and their first N-trifluoromethanesulfonyl-substituted imides were synthesized. The results are compared with the data on the reaction of the same substrates with chloramine B. The distinctly pronounced stabilizing effect of a highly electronegative trifluoromethanesulfonyl group was observed, which decreased the reactivity of N-trifyl-substituted sulfimides with respect to electrophilic reagents and increased their stability. Mass spectra of isomeric cyclic organosilicon N-trifluoromethanesulfonyl-substituted sulfimides VII, X, their acyclic analog III, and the product of the decomposition of the latter at the Si-C(S) bond IV were studied. The mechanism of formation of sulfimides in nonaqueous media is discussed.     

Expansion of an arbitrary function in products of spherical functions

A formula for expanding an arbitrary function defined in the interval (0,1) into a series in products of spherical Legendre functions of the first and second kinds is presented. Examples of expansions of this type are given. Zh. Tekh. Fiz. 67, 123–126 (June 1997)     

Lithiation of 3,3-Dimethyl-3-silathiane as a Route to α-Substituted Six-Membered Cyclic Organosilicon Sulfides

Russian Journal of General Chemistry -     

Activation of the Surface of Carbon and Nitrogen-Doped Carbon Nanotubes by Calcium Nitrate: Catalytic Properties of Cobalt Supported Catalysts of the Fischer–Tropsch Process Based on Them

Kinetics and Catalysis - Using the methods of scanning and transmission electron microscopy (SEM and TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, the influence of...     

Energy characteristics of carbon spheres

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Conformational rivalry of geminal substituents in silacyclohexane derivatives: 1-Phenyl vs. 1-OR,R=H or Me

Molecular structure and conformational equilibria of 1-methoxy- 1 and 1-hydroxy-1-phenylsilacyclohexanes 2 were studied by quantum chemical (QC) calculations and combined gas electron diffraction/mass spectrometry (GED/MS). Both molecules may exist in 5 or 6 forms, differing from each other by the substituents' position: (i) axial or equatorial and (ii) rotational orientation relative to the six-membered ring frame. The contribution of axial forms of both compounds varies from 35 to 60% depending on the theoretical method applied. From the GED data, the summarized molar fractions of the conformers were found to be Ph_ax:Ph_eq = 70(15):30(20) and 50(20):50(20)% which corresponds to ΔG = G_ax–G_eq = ?0.55(46) and 0.00(56) kcal/mol, for compound 1 and 2, respectively. The concentration of the Ph_ax forms of 1-phenyl-1-(X)-silacyclohexanes (X = H, HO, Me, MeO and Me₂N) increases with the size of the second substituent at the silicon atom: 38(10)<50(20)<58(15)<70(15) <80(15)%.     

Stereochemistry of the Horner-Emmons reaction between 3-functionally substituted 2-methyl-2-propenylphosphonates and aliphatic aldehydes. 4. Effect of the nature of the aliphatic aldehyde and concentration of the starting reagents

The double bond formed in the Horner-Emmons reaction has only E configuration independently of the structure of the saturated linear, -branched, and -branched aliphatic aldehydes upon their reaction with the diethyl ester of 3-ethoxycarbonyl-2-methyl-2-propenylphosphonic acid, while the ratio of the2E,4E and2Z,4E isomers in the reaction product varies only from 5842 to 6238. An increase in the aldehyde concentration leads to an increase in the fraction of the2Z,4E isomer in the ethyl ester of 2E/Z,4E-3,7-dimethyl-2,4-octadienoic acid formed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1417–1421, June, 1990.     

Stereochemistry of the Horner-Emmons reaction of 3-functionalized 2-methyl-2-propenylphosphonates with aliphatic aldehydes 5. Effects of base anion,temperature, solvent,and addition of a crown ether

Taking the reaction of diethyl 3-ethoxycarbonyl-2-methyl-2-propenylphosphonate with 3-methylbutanal as an example, it has been shown that the composition of the equilibrium mixture of the E- and Z-isomers of the starting phosphonate formed in the presence of bases is independent of the base anion (KOH or K₂CO₃) and the solvent (benzene or DMSO). In the mixture of 2E,4E- and 2Z,4E-isomers of ethyl 3, 7-dimethyl-2, 4-octadienoate formed in this reaction, the proportion of the 2E, 4E-ester falls as the temperature is reduced from +40 to –40C; the proportion of the 2E, 4E-ester in the heterophase system base/aprotic solvent increases with increasing polarity; and in the presence of 10 mole % of 18-crown-6 ether the proportion of the 2E, 4E-isomer is increased, being greater than 50% in all solvents. These findings indicate that the stereochemical outcome of the reaction depends on the balance between the phase systems and the chemical equilibria, including the formation, dissociation, and reactions of the intermediate products.For previous communication, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2544–2550, November, 1990.