Investigation of Sulfur Extrusion from a Cyclic Dialkoxy Disulfide

Synthesis and Hydrogen Sulfide Releasing Properties of Diaminodisulfides and Dialkoxydisulfides

Heterosubstituted disulfides are an understudied class of molecules that have been used in biological studies, but they have not been investigated for their ability to release hydrogen sulfide (H₂S). The synthesis of two sets of chemicals with the diaminodisulfide (NSSN) and dialkoxydisulfide (OSSO) functional groups was reported. These chemicals were synthesized from commercially available sulfur monochloride or a simple disulfur transfer reagent. Both the diaminodisulfide and dialkoxydisulfide functional groups were found to have rapid rates of H₂S release in the presence of excess thiol. The release of H₂S was complete with 10 min, and the only byproducts were conversion of the thiols into disulfides and the amines or alcohols originally used in the synthesis of the diaminodisulfide or dialkoxydisulfide functional groups. These results will allow the design of H₂S releasing chemicals that also release natural, biocompatible alcohols or amines. Chemicals with the diaminodisulfide and dialkoxydisulfide functional groups may find applications in medicine where a controlled, burst release of H₂S is needed.

Acid-Mediated Sulfonylthiolation of Arenes via Selective Activation of SS-Morpholino Dithiosulfonate

A trifluoroacetic-acid-mediated desulfurilative sulfonylthiolation of arenes using SS-morpholino dithiosulfonate is described. This system is based on selective activation of the morpholino group over the tosyl group of the doubly transformable sulfur surrogate. Mechanistic studies suggested that the reaction proceeds through electrophilic aromatic substitution followed by sulfur extrusion. The wide substrate scope of this reaction and the transformability of the resulting thiosulfonates enable expeditious access to divergent multifunctionalized sulfides.

Synthesis of fully substituted pyrazoles from pyridinium 1,4-zwitterionic thiolates and hydrazonoyl chlorides via a [[3 + 3] - 1] pathway

A novel and practical protocol for the synthesis of fully substituted pyrazoles from pyridinium 1,4-zwitterionic thiolates and hydrazonoyl chlorides in excellent yields under mild conditions is described. The transformation proceeds via an unusual [[3 + 3] - 1] pathway, which involves a formal [3 + 3] cascade cyclization followed by a spontaneous ring-contraction/sulfur extrusion reaction from 4H-1,3,4-thiadiazine intermediates.