Synthesis of a bis-mesylate salt of 4-amino-n-(1-((3-chloro-2-fluorophenyl)amino)-6-methylisoquinolin-5-yl)thieno[3,2-d]pyrimidine-7-carboxamide and intermediates thereto

Abstract

A manufacturing process to a bis-mesylate salt 1b of the pan-RAF inhibitor 4-amino-n-(1-((3-chloro-2-fluorophenyl)amino)-6-methylisoquinolin-5-yl)thieno[3,2-d]pyrimidine-7-carboxamide. The process 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 penultimate intermediate 7. The final amide coupling of 7 and 2 was accomplished by a mild and safe protocol employing N,N,N',N′-tetramethylchloroformamidinium hexafluorophosphate (TCFH) as the coupling reagent, to produce a 1:1 adduct of the freebase and THF. The adduct afforded compound 1b with excellent yield, purity, and form stability on a multikilogram production scale after reaction with MsOH and recrystallization. The methods are able to produce a compound having upwards of 95% purity.