Discovery and Development of an Efficient, Scalable, and Robust Route to the Novel CENP-E Inhibitor GSK923295A

The discovery and development of an efficient manufacturing route to the CENP-E inhibitor 3-chloro-N-{(1S)-2-[(N,N-dimethylglycyl)amino]-1-[(4-{8-[(1S)-1-hydroxyethyl]imidazo[1,2-a]pyridin-2-yl}phenyl)methyl]ethyl}−4-[(1-methylethyl)oxy]benzamide (GSK923295A) is described. The existing route to GSK923295A was expensive, nonrobust, used nonideal reagents, and consistently struggled to deliver the API needed for clinical studies. The new synthesis commences from the readily available l-phenylalaninol, which is smoothly converted through to GSK923295A using key Friedel−Crafts acylation as well as selective acylation chemistries. Downstream chemistry to GSK923295A is both high yielding and robust, and the resulting process has been demonstrated first on the kilo scale and subsequently in the pilot plant where 55 kg was successfully prepared. The resulting process is simple, uses cheaper raw materials, is greener in that it avoids using aluminum, tin, and bromination chemistries, and obviates the need for chro...