Unusual Thermolysis of Diisobutyl Polysulfides

Russian Journal of Organic Chemistry -     

Synthesis of 2-(2-selenienyl)pyrrole from methyl-2-selenienylketoxime and acetylene

The reaction of methyl-2-selenienylketoxime with acetylene in KOH-DMSO gives 2-(2-selenienyl)pyrrole and its 1-vinyl derivative.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 708–710, May, 1992.     

Synthesis and redox activity of sulfurized poly(methylene polysulfides)

Redox-active sulfurized poly(methylene polysulfides) ?[CH₂S _y ] _n ? (y = 4–22) were prepared by deep sulfurization of poly(methylene di- and trisulfides) with elemental sulfur. The use of the substances obtained as an active cathode material of rechargeable lithium cells ensures their cycling with a specific discharge capacity of 418–550 mA h g^?1.     

High-Temperature Synthesis of Thiophene from Bis(2-chloroethyl) Sulfide

Gas-phase reaction of bis(2-chloroethyl) sulfide (Yperite) with acetylene at 550–700°C leads to formation of thiophene in 45% yield, the conversion of the initial sulfide being complete. The yield of thiophene reaches 63–68% in the thermolysis of a mixture of acetylene, bis(2-chloroethyl) sulfide, and lower organic disulfides.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 6, 2005, pp. 910–912.Original Russian Text Copyright © 2005 by Voronkov, Levanova, Sukhomazova, Russavskaya, Deryagina, Korchevin.     

Gas-phase Reaction of 2-Chlorothiophene with Hydrogen Sulfide in the Presence of Alcohols

The effect of methanol and ethanol on the route of the gas-phase reaction of 2-chlorothiophene with hydrogen sulfide, leading to 2-thiophenethiol and to bis(2-thienyl) sulfide, has been investigated. It was found that methanol significantly enhances this reaction and increases its selectivity for the thiol at higher temperatures than without the initiator. The optimal conditions were achieved at 570°C in the presence of 10 mole % of methanol when the conversion of the 2-chlorothiophene in the reaction with hydrogen sulfide reaches 98% and the yield of the thiophenethiol (43%) exceeds that of the bis(2-thienyl)sulfide (31%). In the absence of methanol the 2-thiophenethiol is formed only at 510-540°C in just 17% yield, the basic reaction product being the indicated sulfide (52% yield); the conversion of the 2-chlorothiophene does not exceed 54%.     

Geminal conjugation in disulfides

Some aspects of the spatial and electronic structure of disulfides XSSX (X = H, Alk, Ph, Hal) are considered. It is shown that the growth of the geminal n_s-σ_SX* conjugation efficiency leads to a shortening of the SS bond that is more than three times as large as the simultaneous SX bond lengthening. The positive effective charge on the sulfur atom also increases as a result of this conjugation. These effects increase with the growth of - I and + M abilities of the substituents X. The SK_a line shifts and the HOMO bonding degree (Delta;n_S) have been measured by the X-ray fluorescence spectroscopy method for dialkyl disulfides (Alk = Me, Et, Pr, i-Pr, Bu, i-Bu, t-Bu, C₅H₁₁, C₈H₁₇, H₂NCH₂CH₂, CH₂CH  CH₂, CH₂Ph) and S₈. With the help of Δn_S values that are proportional to the n_S–σ_SC* conjugation efficiency, the sequence of the enhancement of the geminal conjugation efficiency has been established for the disulfides investigated. In the framework of the n_S–σ_SS* geminal conjugations, the shortening of the SS bonds in S₈ is explained. © John Wiley & Sons, Inc.     

Thermal reactions of organyl chalcogenides with α,β-unsaturated aldehydes

Thermal gas-phase reactions of acrolein, cinnamaldehyde, and benzaldehyde with diorganyl chalcogenides and diorganyl dichalcogenides were studied. Acrolein does not react with chalcogenides at 300–600°C but completely decomposes under reaction conditions. At 600–650°C, cinnamaldehyde reacts only with diorganyl selenides and diselenides to give benzoselenophene. Its highest yield (53%) is achieved in the reaction with dimethyl diselenide at 630°C and at an equimolar ratio of the reactant. The gas-phase reactions of benzaldehyde at 400–500°C afford chalcogen-containing derivatives of several types, among which thioanisole and its selenium or tellurium analogs predominate. The mechanisms of the above reactions were discussed in terms of homolytic substitution of the formyl group at unsaturated carbon atoms by chalcogenyl radicals.     

Addition of hydrohalic acids to acetylenic ketones of the thiophene series

The synthesis of -chloro(bromo)vinyl ketones of the thiophene series was accomplished by the addition of hydrogen chloride and hydrogen bromide to acetylenic ketones of the thiophene series. The sequence of addition of the hydrogen halide was proved by alternative synthesis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1350–1352, October, 1971.