Averaging of randomly perturbed evolutionary equations

Evolutionary equations with coefficients perturbed by diffusion processes are considered. It is proved that the solutions of these equations converge weakly in distribution, as a small parameter tends to zero, to a unique solution of a martingale problem that corresponds to an evolutionary stochastic equation in the case where the powers of a small parameter are inconsistent.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 45, No. 7, pp. 963–971, July, 1993.     

1-Trifluoromethyl-2-chloroethylthiolated carbonyl compounds: Synthesis and properties

1-Trifluoromethyl-2-chloroethylsulfenyl chloride thiolates enolizible ketones, forming products of mono- and disubstitution. The properties of the resultant sulfides are determined by the presence in the molecule of two acidic CH centers. Thus, bromination proceeds at the ambident center and reaction with bases leads to (1-trifluoromethylvinyl) sulfides which are able to undergo intramolecular cyclizations and Diels-Alder reactions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 676–681, March, 1991.     

2-(Methylthio)pentafluoropropene

2-(Methylthio)pentafluoropropene was obtained by dehydrofluorination of methyl 2H-hexafluoroisopropyl sulfide by the BF₃ · NEt₃ complex. Its reactivity with respect to allyl alcohol and hexamethyldisilazane was studied. The electrophilicity of 2-(methylthio)penta-fluoropropene was compared with the properties of terminal polyfluoroalkenes whose behavior in these reactions has been studied previously.Perfluoroisobutylene also reacts with allyl alcohol in the absence of protophilic agents.3,4Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 80–84, January, 1994.     

Synthesis and properties of 2-trifluoromethyl-substituted 4-pentenoic and 3,4-pentadienoic acids and their esters

The hydrolysis of the acid fluorides of 2-fluorocarbonyl(methoxycarbonyl)-2-trifluoromethyl-4-pentenoic acids (I) and (II), and of 2-fluorocarbonyl-(methoxycarbonyl)-2-trifluoromethyl-3,4-pentadienoic acids (III) and (IV) gave, under mild conditions, 2-trifluoromethyl-4-pentenoic acid (V) and 2-trifluoromethyl-3,4-pentadienoic acid (VII) or their methyl esters (VI) and (VIII). The reactivity of these compounds was studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2805–2809, December, 1991.     

Comparison of α- and β-trifluoromethylsubstituted acrylic acids in their reactions with thiols

α-(Trifluoromethyl)acrylic acid (1) and γ,γ,γ-trifluorocrotonic acid (2) add AcSH (exothermally and at 100 °C, respectively) in the absence of a catalyst to form products of β-thiolation, which can be easily hydrolyzed to the corresponding β-mercaptoalkanoic acids. Thiols also add regiospecifically to acids1 (in the absence of a catalyst) and2 only in the presence of trifluoromethanesulfonic acid as the catalyst) when heated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1230–1232, June, 1997.     

Reaction for nucleophilic opening of thiirane ring by thiols

Conclusions The nucleophilic opening of the thiirane ring by thiols proceeds with greater difficulty than that of the oxirane ring. Aliphatic and aromatic thiols in nonpolar solvents, using homogeneous catalysis by bases, can be unambiguously mercaptoethylated by selecting the necessary ratios of thiol compound and ethylene sulfide.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 660–662, March, 1975.     

The structure and CH-acidity of CF3-substituted β-thiolactones. A theoretical study

Ab initio calculations of the molecules of CH₃- and CF₃-substituted β-propiothiolactones and the productsof their deprotonation were carried out by the restricted Hartree—Fock method with full geometry optimization using the 6–31 G^* basis set. Peculiarities of the geometry and electronic structure of the systems in question were established. Only 2-methyl-β-propiothiolactone forms a mesomeric stabilized carbanion in the case of proton abstraction from the α-position of thiolactone cycle. Carbanions of 3-methyl, 2-, and 3-thrifluoromethyl-β-propiothiolactones are stabilized due to the ring opening to form ketene thiolate ions. The CH-acidity of fluorine-containing β-thiolactones is much higher than that of nonfluorinated analogs (the differences in the deprotonation energies are 13.4 to 25.2 kcal mol⁻¹). Deceased. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1719–1725, September, 1998.     

Thermal ene reactions of methyl 3,3,3-trifluoro-2-R-sulfonyliminopropionates. Synthesis of γ,δ-unsaturated derivatives ofα-amino α-trifluoromethylcarboxylic acids

Thermal ene reactions of methyl 3,3,3-trifluoro-2-methanesulfonyliminopropionate and methyl 2-benzenesulfonylimino-3,3,3-trifluoropropionate with terminal alkenes afford derivatives of ,-unsaturated -amino -trifluoromethylcarboxylic acids in one step.