An Efficient Second-Generation Manufacturing Process for the pan-RAF Inhibitor Belvarafenib

Herein, the development of a streamlined manufacturing process for the pan-RAF inhibitor belvarafenib (GDC-5573) is reported. The process to belvarafenib features a number of efficient key reactions, including a robust and scalable Pd-catalyzed carbonylation reaction to generate thienopyrimidine 2 and a highly chemoselective Pt/V/C-catalyzed nitro group reduction to access the penultimate intermediate 3. The final amide coupling was accomplished by a mild and safe protocol employing N,N,N′,N′-tetramethylchloroformamidinium hexafluorophosphate as the coupling reagent, which afforded belvarafenib on a multikilogram production scale after recrystallization.