Streamlined process for the esterification and ketalization of shikimic acid en route to the key precursor for oseltamivir phosphate (Tamiflu™)

Abstract

In an effort to streamline the current process for the key precursor en route to Tamiflu™ (oseltamivir phosphate), the ketalization reaction was re-evaluated for areas of improvement. Removal of thionyl chloride was a priority from a EH & S and operational perspective. Finally, the reduction of solvents and telescoping steps would improve throughput and minimize waste streams.