A Simple Way of Synthesis of Bisethylthiopolymethylene Sulfides EtS(CH2S)nEt

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.     

Reactions of Diorganyl Disulfides with Dihaloalkanes in Basic Reductive Media. Synthesis of Bis(organylthio)alkanes

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.     

A New Route to 1,2,3-Propanetrithiol

A new procedure was developed for preparing 1,2,3-propanetrithiol from available initial compounds. 1,2,3-Trichloroethane reacts with sodium disulfide prepared by dissolving sulfur in the system NaOH-N₂H₄ · H₂O-H₂O to give a disulfide dendrimeric polymer, thiokol, in almost quantitative yield. This polymer is subjected to reductive cleavage with an alkaline solution of hydrazine hydrate, which is followed by acidification with HCl. The yield of 1,2,3-propanetrithiol exceeds 60%. The synthesis can be performed as a one-pot procedure.     

New Preparative Procedure for the Synthesis of Chloroalkyl 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.     

New Routes to Poly(Alkylene Sulfidoselenides)

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.     

Reactions of Bielectrophiles (ClCH2CH2)2Y with Sulfur in Basic Reducing Systems

A simple procedure was developed for preparing bis(-mercaptoethyl) ether and bis(-ecraptoethyl) sulfide from commercially available chemicals: elemental sulfur, alkali, and bis(-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(-chloroethyl) ether are soluble in organic solvents; they were studied by ¹H NMR.