Generalized synthesis and physical properties of dialkoxy disulfides

A substrate study was undertaken in order to probe the scope of S2Cl2 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 la 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 la 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.</p

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 (S2Cl2) serve as important alterations to the synthetic method. Their physical properties have been characterized, revealing some discrepancies with the literature.</p

Generalized synthesis and physical properties of dialkoxy disulfides

A substrate study was undertaken in order to probe the scope of S2Cl2 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 la 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 la 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.</p

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 (S2Cl2) serve as important alterations to the synthetic method. Their physical properties have been characterized, revealing some discrepancies with the literature.</p

Synthesis of new cyclic thionosulfites

The reaction of a series of 1,2-diols with S2Cl2, 1,1'-thiobisbenzimidazole (4a), and 1,1'-dithiobisbenzimidazole (4b) provides the corresponding thionosulfites, ROS(S)OR (2), in moderate to good yield.</p

Synthesis of new cyclic thionosulfites

The reaction of a series of 1,2-diols with S2Cl2, 1,1'-thiobisbenzimidazole (4a), and 1,1'-dithiobisbenzimidazole (4b) provides the corresponding thionosulfites, ROS(S)OR (2), in moderate to good yield.</p