Caltech researchers have developed a method to scale up the use of samarium diiodide, a valuable reagent in pharmaceutical synthesis. Previously limited to laboratory use, the new technique allows the reagent to recycle itself within a single reaction, according to a news release from Caltech.
"The reagent is air sensitive, so you often have to prepare the solution fresh, right before the reaction," says Caltech graduate student Chungkeun Shin, who works in the lab of Sarah Reisman, Bren Professor of Chemistry and the Norman Davidson Leadership Chair of Caltech's Division of Chemistry and Chemical Engineering. "And we often have to use large amounts of it, even in small reactions, so it's not practical for running industrial-scale reactions."
The key breakthrough addresses the formation of a stubborn samarium-oxygen bond that renders the reagent inactive. Using a mild acid, researchers can cleave this bond, converting the bound oxygen into an alcohol and freeing the samarium for reuse. This process eliminates the need for large amounts of solvents and fresh preparations, making industrial-scale reactions more feasible.
"It's been very difficult to recycle samarium back to its active state until now," explains Caltech graduate student Emily Boyd who works in the lab of Jonas Peters, Bren Professor of Chemistry and director of the Resnick Sustainability Institute at Caltech. Boyd and Shin are co-lead authors of the new study.
The new method has potential applications in process development and drug discovery, potentially enabling the industrial-scale synthesis of complex molecules like taxol, an anticancer agent. It also has implications for improving nitrogen fixation processes, which are crucial for producing ammonia and other essential nitrogen compounds.
