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The reaction of 3,3,3-trifluoro-1-(2-thenoyl)acetone with sulfur—hydrazine hydrate—alkali and hydrazine hydrate—alkali systems is effected by reductive fission of the trifluoroacetyl group and leads to the formation of nitrogen-containing derivatives of 2-acetylthiophene. Sodium polysulfide assists the reductive fission of 3,3,3-trifluoro-1-(2-thenoyl)acetone.

A reaction of the polycondensation product of bis(thien-2-yl)sulfide and formaldehyde with elemental sulfur affords a polymer containing polysulfide moieties (S-content = 67.2%). When used as active cathode material for model lithium rechargeable cells, the polymer shows the discharge capacity of 620 mA·h· g−1 at the first cycle.

Direct reaction of propan-1,3-diselenol with thiophene-2-carbaldehydes in trimethylchlorosilane medium is studied. Synthetic procedure for preparation of the previously unknown 1,3-diselenanes of thiophene series is developed. Structure of the newly obtained compounds is established by 1H, 13C, and 77Se NMR spectroscopy. Chromatomass spectrometric stidy of the products obtained is carried out. In some cases reaction may be directed to the synthetis of new types of polymers of original structure.

A highly selective method was developed for preparation of previously unknown 1,3-dithiolanes and 1,3-dithianes by reactions of thiophene-2-carbaldehyde and its analogs with alkanedithiols under the action of trimethylchlorosilane.

Gas-phase reactions of chloroarenes (ClC6H4X, X = H, 4-CH3, 4-OH, 4-Cl, 4-CF3) with hydrogen sulfide or its precursors were investigated in the presence of methanol, which was a stronger H-donor than hydrogen sulfide. Introducing methanol increased the selectivity of arenethiols formation at X = H and 4-CH3 and did not affect the reaction selectivity at acceptor X. The efficiency of methanol influence was considered from the viewpoint of free-radical reaction mechanism and the stability of the arenethiyl radicals.

A procedure for the synthesis of dithioacetals containing various thiophene fragments was developed on the basis of the reaction of thiophene-2-carbaldehyde and its analogs with thiols in chlorotrimethylsilane.

Thiylation of polyhaloalkanes and Paraform with elemental sulfur activated in hydrazine hydrate-organic amine systems is performed. Monoethanolamine, triethanolamine, and triethylamine were used as amines. The reactions gave thiocols of various structures. The products were characterized by elemental analysis and IR spectroscopy. Reductive cleavage of the synthesized thiocols was performed to obtain di- and polythiols.

The potential surfaces of the reactions of thiols and disulfides with haloalkanes in the gas phase and with participation of a hydrizine molecule were studied quantum-chemically. The stereoelectronic characteristics of the prereaction complexes and reaction products were studied. The transition states were localized. The four-center reaction mechanism is preferable. The increased activation barrier in exchange of thiols with chloroalkanes is the major factor responsible for formation of unsymmetrical chlorinated sulfides.

Liquid-phase thermal reactions of phenylacetylene with the system arene(hetarene)thioldiselenide at 110-180°C proceed through conjugate addition to the phenylacetylene triple bond of one alkylselanyl and one arene(hetarenesulfanyl groups to form 2-alkylselanyl-2-[aryl(hetaryl)sulfanyl]-1-phenylethenes and 1-alkylselanyl-2-[aryl(hetaryl)sulfanyl]-1-phenylethenes. Therewith, direct addition of thiols to phenylacetylene slows down.

Sufur-selenium, sulfur-tellurium, selenium-tellurium, and sulfur-selenium-tellurium mixtures readily dissolve in the hydrazine hydrate-alkali system to form chalcogenide anions. Alkylation of the latter with ethyl bromide results in preferential formation of diethyl disulfide, diethyl diselenide, and diethyl ditelluride. Tellurium reacts with dichloromethane in the presence of sulfur, yielding poly(methylene ditelluride), the reaction in the presence of selenium gives rise to poly(methylene selenotellurides), while in the sulfurselenium-tellurium mixture polymers containing all the components are formed.

Six azomethine derivatives of 2,2'-dithienyl sulfide and five of 2,2'-bithienyl have been synthesized for the first time.

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%.

Poly(methylene diselenide), -[-CH2Se2-] n -, when alloyed with sulfur in a 1-4 molar excess of the latter, gives dark orange rubber-like poly(methylene seleno-polysulfido-selenides), -[-CH2SeS m Se-] n -, where m =1-4 representing a new class of S-Se organic polymers having no C-S bonds. At molar ratio sulfur:poly(methylene diselenide) equal to 16 sulfur content does not exceed m =4. The selenium part of the polymer, while alloying with sulfur, is removed from the polymer and forms the compound with sulfur. The polymers demonstrate reversible redox properties and can be employed as active cathode materials in rechargeable lithium cells.

A simple procedure was developed for preparing bis(β-mercaptoethyl) ether and bis(β-ecraptoethyl) sulfide from commercially available chemicals: elemental sulfur, alkali, and bis(β-chloroethyl) ether or sulfide, based on thiylation with elemental sulfur of these substrates in the aqueous system hydrazine hydratealkali, with initial formation of the corresponding polysulfide polymers (thiokols). Their reduction with the system hydrazine hydrate-alkali, followed by acidification of dithiolate anions, yields the corresponding dithiols. Thiokols based on bis(β-chloroethyl) ether are soluble in organic solvents; they were studied by 1H NMR.

A convenient preparative synthesis of bis(organylthio)alkanes was developed. It is based on alkylation with dihaloalkanes of solutions of diorganyl disulfides in the basic reductive system hydrazine hydrate-alkali. The generation of organylthiolate anions from disulfides and the subsequent reaction of the anions with dihaloalkanes are performed in one reaction vessel without isolation of intermediate alkali metal thiolates. At the same time, the reactions of diphenyl or dithienyl disulfides with dihaloalkanes result in substitution with the thiolate anions of only one halogen atom to give the corresponding unsymmetrical sulfides. In certain cases in the presence of excess alkali the latter sulfides are dehalogenated to form alkyl vinyl sulfides.

Reaction of thiols with dihaloalkanes in the system hydrazine hydrate-base leads to alkyl(chloroalkyl) sulfides with different positions of the chlorine atom with respect to sulfur. The developed one-step procedure for the synthesis of such unsymmetrical sulfides is most suitable for arenethiols and alkanethiols having a long polymethylene chain. The reaction mechanism is discussed.

Preparation of solid polymers with varied content of sulfur by condensation of 1,2,3-trichloropropane-rich wastes from epichlorohydrin production with sodium polysulfide Na2Sx (x = 1-4) generated by reductive dissolution of sulfur in the hydrazine hydrate-alkali system was studied.

A procedure was developed for preparing mixed poly(alkylene sulfidoselenides) by simultaneous dissolution of sulfur and selenium in basic reducing systems NaOH (KOH)-N2H4·H2O-H2O, followed by alkylation of the resulting solutions with bielectrophilic agents.

Two methods of synthesis of bisethylthiopolymethylene sulfides RS(CH2S) n R (R = Et, n ≥ 1) are developed. Both approaches are based on the reductive cleavage of the S-S bonds in diethyl polysulfides or a mixture of diethyl polysulfides with elementary sulfur by the system: hydrazine hydrate-base. Subsequent alkylation of the formed thiolate anions with dichloromethane leads to the formation of mixtures of oligomeric bisethylthiopolymethylene sulfides with a predominance of compounds with n = 1, 2.

The review summarizes the results of the authors' studies on thermal reactions of sulfur, hydrogen sulfide, and their derivatives with organic compounds, performed since 1944 till 2000.

Tribenzylphosphine oxide readily and stereoselectively reacts with aliphatic, aromatic, and heteroaromatic aldehydes in the presence of strong bases yielding exclusively (or predominantly) E-isomers of 1-organyl-2-phenylethenes and dibenzylphosphinic acid.

Reaction of dialkyl diselenides R2Se2 (R = Me, n-Bu) with sulfur at room temperature in the presence of the catalytic system DMSO-Na2S·9H2O-triethylbenzylammonium chloride, as well as at 55-60°C in the presence or in the absence of catalysts leads to the insertion of from one to six atoms of sulfur into the Se-Se bond. Bis(methylseleno) polysulfides MeSeSnSeMe with n = 5-6 gradually liberate sulfur on keeping. Dibutyl diselenide is less active than dimethyl diselenide, and diphenyl diselenide does not react with sulfur in boiling carbon disulfide. At 55-60°C a small portion of selenium in dialkyl diselenides passes into unreacted sulfur which is indicative of cleavage of the C-Se bonds in bis(methylseleno) polysulfides.

The reductive destruction of poly(methylene sulfides) and poly(methylene polysulfides) in the system hydrazine hydrate - NaOH at 70–1 15°C involves cleavage of the C-S bond and the formation of sulfide, disulfide and trisulfide anions. Nitrogen and methane are main gaseous products of reduction. The reduction of C-S bonds in these polymers is proven by electrochemical methods.

Published data on thermolysis of organic compounds of divalent sulfur and on thermal synthesis involving these compounds are summarised. The bibliography includes 201 references.

Redox-active sulfurized poly(methylene polysulfides) −[CH2Sy]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.

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.

The substitutent effect on the self-thiylation of 2-thiophenethiols was studied. Experimental results and quantum chemical calculations suggested possible mechanisms for this reaction dependent on the reaction conditions.

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.

Acetylene and its derivatives have been used for the first time as “traps” for vinylthiyl radicals generatedin situ from hydrogen sulfide and haloethylenes in gas-phase processes. The competitive reactivity of the vinylthiyl radicals has been studied at 500–570 °C in the presence of two chemical “traps.” The efficiency of chemical “traps” for the vinylthiyl radicals decreases in the following sequence: HC≡CPh > HC≡CH > MeC≡CH > CH2=CHCl. Acetylene is a more efficient “trap” for the vinylthiyl radicals than 1,2-dichloroethylene, from which they have been generated. The β-phenylvinylthiyl radicals generated during cothermolysis of halostyrene-hydrogen sulfide-acetylene component ternary systems undergo first of all intramolecular ring closure to give benzothiophene, which is a thermodynamically favorable system; the reaction of these radicals with acetylene and its derivatives occurs much more slowly than heterocyclization. Phenylacetylene is a more efficient “trap” than acetylene. α-Phenylvinylthiyl radicals mostly react with acetylene to yield 2-phenylthiophene.

Gas-phase thermolysis of xanthic acid esters and their reaction with acetylene at 250–600°C have been studied for the first time. The direction of the thermolysis is determined by the nature of the substituents at the oxygen and sulfur atoms. The main products of the thermolysis are gaseous hydrocarbons, carbon monoxide and hydrogen sulfide. The yields of liquid products of the thermolysis and of the reactions with acetylene are 4–46%. The role of thiyl radicals in thiophene molecule formation and reaction routes to carbon disulfide, dithiocarbonates, and stilbene are discussed.

Two new synthetic approaches to 1,2-dithiole-3-thione are proposed. The title compound is formed by thermolysis of dipropyl polysulfides (n-Pr)2Sx (x = 3–4) and thermal decomposition of polysulfide dendrimers under reduced pressure. The latter reaction may be recommended for utilization of organochlorine waste products in the manufacture of epichlorohydrin, which are used for the synthesis of dendrimers.

Gas-phase reaction of diethyl disulfide or “disulfide oil” with acetylene performed in the presence of methanol provides an essentially more selective thiophene formation. The yield of thiophene increases by 20–30%, and the yield of by-products decreases by half.

The main types of radicals formed in initiated reactions of organic compounds of selenium and tellurium, detection methods, and their physico-chemical properties and reactivity are presented in this review.

Bis(ethylseleno)alkanes were obtained by reductive cleavage of the Se-Se bond in diethyl diselenide with the system hydrazine hydrate-alkali, followed by alkylation with dihaloalkanes. A general preparative method of synthesis of bis(alkylseleno)alkanes of various structure was proposed.

Furanthiols and selenols have been synthesized by a modified procedure via organolithium derivatives, with the formation of trimethylsilyl ethers as intermediate products. It has been shown that the thiols as well as the selonols undergo autoconversions when standing in air and in the presence of triethylamine with the formation of furylthio-(seleno)-substituted thio-(seleno)-butyrolactones.

At the alkylation of monoethanolamine vinyl ether with 2-chloro-5-(chloromethyl)thiophene in ethyl alcohol (60-70°C) a product of disubstitution and transvinylation, viz. N,N-bis(5-chloro-2-thienylmethyl)-N-(2-hydroxyethyl)ammonium chloride is formed. The analogous reaction in the absence of solvent proceeds with the formation of N-(5-chloro-2-thienylmethyl)-N-(2-vinyloxyethyl)amine.

Dissolution of sulfur in the system hydrazine hydrate-alkali leads to strong activation of hydrazine, so that the latter readily reacts at room temperature with aldehydes of the aromatic and thiophene series to give the corresponding aldehyde azines in high yield. The mechanism of activating effect of sulfur is discussed.

Chloromethylation of bis(2-thienyl) sulfide is accompanied by fast polycondensation of the primary chloromethylation product with the initial sulfide. The reaction gives a new polymer in which the thiophene rings are alternately separated by sulfur atoms and methylene groups. Fusion of the polymer with molecular sulfur gave new sulfur-enriched polymers whose specific electric conductivity is comparable with that of organic semiconductors.

The principal types of radicals formed in various types of initiation of the reactions of organic compounds of selenium and tellurium, the methods for their detection, and their properties and reactivities are examined. The bibliography includes 98 references.

The review presents data on the methods of generation and properties of thiyl radicals. The results of studies on the reactivities of thiyl radicals in thermal processes, permitting the synthesis of a wide variety of organic sulphur compounds and compounds of other types, are surveyed. The bibliography includes 167 references.