DMSO is used as a solvent in a documented route to an esomeprazole sulfide intermediate. It supports an earlier coupling step, before the sulfide is oxidized to the sulfoxide found in the PPI molecule.
Building the sulfide intermediate
The disclosed process combines a halomethyl-substituted pyridine intermediate with a mercaptobenzimidazole component under basic conditions. One example uses DMSO with an aqueous sodium hydroxide solution. The coupling joins the two fragments through sulfur.
DMSO provides the reaction medium. The mercaptobenzimidazole component supplies the sulfur involved in the linkage. The patent also describes other solvent systems, so DMSO is one documented route choice.
Keep coupling and oxidation separate
The next oxidation changes the sulfide into a sulfoxide. Oxidant selection, selectivity and control of over-oxidation belong to that later operation; they cannot be inferred simply from using DMSO in the coupling.
For the DMSO-containing step, solvent composition, mixing, conversion and intermediate impurities are practical evaluation points. Because this example includes an aqueous component, an ultra-dry requirement should not be assigned without a process reason.
Work-up, solvent recovery and residual-solvent control should follow the established intermediate and API procedures. Review the complete mixture when assessing compatibility and heat removal.
For sourcing, provide YUJI with the coupling-step solvent specification and packaging requirement.