DMSO can supply sulfur in selected reported thiophene-forming reactions. In other reactions it acts as an oxidant or simply as the solvent, so the role must be identified from the actual transformation.
A reported sulfur-transfer application
The study Redox-Divergent Construction of (Dihydro)thiophenes with DMSO describes reaction-dependent roles for DMSO in constructing these sulfur-containing rings. This provides a specific research example of DMSO contributing chemically rather than serving only as a medium.
Other thiophene preparations use a separate sulfur reagent. For example, trithiocarbonate chemistry can use carbon disulfide and base in DMSO. In that case, the sulfur source and solvent are separate materials.
What changes when DMSO is consumed
Include DMSO consumption, sulfur-containing by-products and separation in the process comparison. Establish which atoms enter the product and which components remain in the liquid streams.
Use the reported substrate scope and conditions to assess relevance to a proposed route. Water, assay and impurity requirements must follow that chemistry. Laboratory evidence demonstrates the stated reaction, not routine commercial use for every thiophene product.
For an established sulfur-transfer application, YUJI can review sourcing against the required DMSO specification.