Development of a Scalable Synthesis of a Bruton’s Tyrosine Kinase Inhibitor via C–N and C–C Bond Couplings as an End Game Strategy

A scalable and convergent synthesis of a BTK (Bruton's tyrosine kinase) inhibitor has been developed. Synthetic routes to key intermediates were explored for the scale-up campaign, especially the process for 6-dimethylaminodihydroisoquinolinone, which was prepared via a regioselective cyclization of an isocyanate, mediated by AlCl3. Improved routes to key building blocks were demonstrated by expedient multikilogram productions. The target compound was assembled through a Pd-catalyzed amidation reaction followed by a Suzuki–Miyaura cross-coupling reaction.