Potassium thiotosylate

Potassium thiotosylate [28519-50-8] M 226.4. Recrystallise from absolute EtOH and dry at 130°. In wet EtOH the monohydrate can be obtained. [J Gen Chem USSR (Engl Transl) 28 1345 1958.]... 

The a,a -dioxothione 109 can be generated from indan-l,2,3-trione using potassium thiotosylate as the sulfur transfer reagent and has been trapped as its [4+2]-cycloadduct 110 (Scheme 66). A 1,3-sulfinate migration from S — O is involved . 

C. Ethylene Dithiotosylate. To 200 ml. of ethanol containing 10-20 mg. of potassium iodide is added 45.3 g. (0.2 mole) of potassium thiotosylate and 18,8 g. of ethylene dibromide. The mixture is refluxed with stirring for 8 hours in the dark and under a nitrogen atmosphere. The solvent is removed, and the resulting white solid is washed with a mixture of 80 ml. of ethanol and 150 ml. of water. After decantation, the solid is washed three times with 50-ml. portions of water and then recrystallized from approximately 150 ml. of ethanol to yield 28.7 g. of crude product, m.p. 72-75°. Three reerystallizations from a mixture of ethyl acetate and ethanol afford 24 g. (60%) of white crystals, m.p. 75-76° (Note 9). 

Although it has been long known that trimethylene dithiotosylate can be prepared by the reaction of thiotosylate ion with trimethylene dibromide,3 5 various difficulties are associated with the preparation. These problems are to a considerable extent related to the mode of preparation and the resultant purity of potassium thiotosylate. The thiotosylate salt must be free of tosylate and p-toluenesulfiriate impurities, otherwise side products such as tosylates or sulfones will form. One such by-product, tosyltrimethylene thiotosylate,... 

A. Potassium Thiotosylate. Caution This procedure should be carried out in a hood to avoid inhalation of hydrogen sulfide. 

The reactions of potassium thiotosylate and potassium 0,0-dialkyl phospho-rodithioates with alkynyl(phenyl)iodonium salts afford good yields of alkynyl thiotosy-lates and alkynyl phosphorodithioates (equations 63 and 64)87,. Cyclopentenyl products have not been reported in either case. 

The rearrangement of 196 to 197 possibly proceeds via the oxathiirane intermediate 198 <1999T10341>. In the reaction of 199 with potassium thiotosylate, an intermediary oxathiirane 200 is responsible for transfer of up to 18% of the available sulfur to the /ra r-cyclooctene <20000L2519>. 

Potassium persulfate, 207 Potassium thiocyanate, 223 Potassium thiotosylate, 539 Potassium triethylcaiboxide, 314 Prednisolone BMD, 568 Prednisone BMD, 567,568... 

Preparation. Potassium thiotosylate is prepared by the reaction of potassium hydrosulfide with tosyl chloride. This is then treated with trimethylene dibromide to give the reagent. 

In a complementary process, the reaction of active methylene compounds, and derivatives such as the enamine shown, with ditosylated 1,3-dithiols, derived from the reaction of 1,3-dibromo-propane with potassium thiotosylate, can provide unusually substituted 1,3-dithianes (Equation... 

Thiatriazoles.—5-Arylamino-l,2,3,4-thiatriazoles (270 R = NHAr) have been prepared by allowing the corresponding thiosemicarbazides RNHC(S)NHNH2 to react with nitrous acid, " and the reaction between PhSC(S)Cl and potassium thiotosylate gives PhSC(S)S—STos, which reacts with sodium azide to give (270 R = PhS). ... 

Physical Data 1,3-propanedithiol bis(/)-toluenesulfonate) mp 67°C l,2-ethanedithiolbis(/>toluenesulfonate) mp76°C. Preparative Methods treatment of potassium thiotosylate, itself made by the reaction of />-toluenesulfonyl chloride with potassium hydrogen sulfide, with 1,3-dibromopropane or 1,2-dibromoethane in the presence of potassium iodide affords 1,3-propanedithiol bis(/>-toluenesulfonate) and 1,2-ethanedithiol bis(p-toluenesulfonate), respectively. ... 

Hydrogen sulfide is undesirable because its presence can lead to the formation of potassium p-toluenesulfinate. The latter can be formed by the desulfurization of thiotosylate by hydrogen sulfide generated in the reaction of potassium hydrosulfide with tosyl chloride. Attention should be directed toward control of the reaction temperature so that hydrogen sulfide is rapidly removed, thereby ensuing survival of the S—S bond of the thiotosylate. p-Toluenesulfinate ion can displace bromide to form stable sulfones which are less soluble in common solvents, such as benzene, than trimethylene dithiotosylate. Therefore, purification of the dithiotosylate contaminated with the sulfones is difficult to achieve by means of fractional recrystallization. 

The p-toluenesulfonyl chloride should be free of j-toluenesulfonic acid, otherwise potassium p-toluenesulfonate will be formed and will result in the formation of tosylates, rather than thiotosylates. The reagent used by the checkers was obtained from British Drug Houses Ltd. and was purified according to the following procedure.4 A benzene solution of the tosyl chloride was washed with 5% aqueous sodium hydroxide, dried with magnesium sulfate, and then distilled under reduced pressure, b.p. 146° (15 mm.). 

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