Development of a Scalable Synthesis of the Small Molecule TGFβR1 Inhibitor BMS-986260

A scalable route to the small molecule TGFβR1 inhibitor BMS-986260 (1) was developed. This alternative approach circumvented the purification of intermediates by column chromatography and provided access to multikilogram quantities of the key intermediate, 6. The safety aspects of the synthetic approach to the other fragment of the API (TosMIC 10) were critically evaluated, and a robust process for its large-scale synthesis was successfully demonstrated.