Identification and Control of Critical Process Impurities: An Improved Process for the Preparation of Dolutegravir Sodium

Abstract

A four-stage manufacturing route for the preparation of dolutegravir sodium (1) was assessed and optimized leading to a higher yielding, simpler and scalable process. Key improvements in the process include the development of mild workup procedure by selective derivatization of a difficult to remove a process impurity using tert-butyldimethylsilyl chloride. Metal-based hydrogenation-free O-debenzylation is optimized, and the critical isomeric impurity formed was identified and eliminated from the process by the establishment of a proper control strategy.