A Practical and Scalable Synthesis of a Glucokinase Activator via Diastereomeric Resolution and Palladium-Catalyzed C–N Coupling Reaction

Abstract

Here we describe the research and development of a process for the practical synthesis of glucokinase activator (R)-1 as a potential drug for treating type-2 diabetes. The key intermediate, chiral α-arylpropionic acid (R)-2, was synthesized in high diastereomeric excess through the diasteromeric resolution of 7 without the need for a chiral resolving agent. The counterpart 2-aminopyrazine derivative 3 was synthesized using a palladium-catalyzed C–N coupling reaction. This efficient process was demonstrated at the pilot scale and yielded 19.0 kg of (R)-1. Moreover, an epimerization process to obtain (R)-7 from the undesired (S)-7 was developed.