Optimization of the synthesis of symmetric aromatic tri- and tetrasulfides

The reaction of aromatic thiols with sulfur dichloride and sulfur monochloride to form the corresponding aromatic trisulfides, 2a-d, and tetrasulfides, 3a-d, has been optimized with respect to yield and purity. The use of pyridine as an amine base and the use of freshly distilled sulfur monochloride (S(2)Cl(2)) serve as important alterations to the synthetic method. Their physical properties have been characterized, revealing some discrepancies with the literature.     

Synthesis of new cyclic thionosulfites

The reaction of a series of 1,2-diols with S(2)Cl(2), 1,1'-thiobisbenzimidazole (4a), and 1,1'-dithiobisbenzimidazole (4b) provides the corresponding thionosulfites, ROS(S)OR (2), in moderate to good yield.     

A novel synthesis of organic diselenapolysulfides

A family of organic polychalcogenides with a common structure of RSeS_xSeR (with x=1, 2, 3 and R=CH₃, Ph, PhCH₂, O₂NC₆H₄CH₂) as well as cyclic 5,5-dimethyl-1,2-dithia-3,7-diselenacycloheptane were synthesized in good yield and high purity from the reaction of Ph₃CS_xCl with corresponding diselenides in chloroform at room temperature. Mechanistic aspects of the insertion involving the formation of an intermediate (RSeS_xCPh₃) are discussed.     

α,α′-diiodosulfides a useful preparation of divinylic sulfides

Symmetric and unsymmetric divinylic sulfides can be prepared almost quantitatively by the elimination of HI by base from the corresponding α,α′-diiodosulfide. These molecules are quantitatively formed in situ from α,α′-$\text{bis}$trimethylsilosulfides and iodotrimethylsilane under mild conditions.     

Generalized synthesis and physical properties of dialkoxy disulfides

A substrate study was undertaken in order to probe the scope of S(2)Cl(2) coupling of alcohols to form dialkoxy disulfides. Compounds 1b and 1f are new; along with 1a, 1c, 1h, and 1j, all of the title compounds are fully characterized, and the yields of 1a and 1c have been optimized from previously reported syntheses. The effect of the R-substituent about the OSSO moiety has been carefully probed as yields vary. A substrate and a solvent study of the coalescence behavior of this class was carried out. The origin of the inherently large barrier to rotation and the resultant thermal decomposition pathway is discussed. Both phenomena are shown to be solvent independent; hindered rotation is substrate independent. The decomposition of 1a is ca. 7 kcal/mol higher than the barrier to rotation about the S-S bond. The combined evidence suggests acyclic unsymmetric homolytic cleavage of the dialkoxy disulfide.     

A facile preparation of vinyl sulfides

Vinyl sulfides are formed in high yield by the alkylation of trimethylsiloxy mercaptides.