BMS-911543 is a complex pyrrolopyridine investigated as a potential treatment for myeloproliferative disorders. The development of a short and efficient synthesis of this molecule is described. During the course of our studies, a Ni-mediated C-N bond formation was invented, which enabled the rapid construction of the highly substituted 2-aminopyridine core. The synthesis of this complex, nitrogen-rich heterocycle was accomplished in only eight steps starting from readily available materials.

BMS-764459 (1) and BMS-763534 (2) are CRF1 antagonists for the treatment of neurological disorders such as depression and anxiety. An efficient synthesis of 1 and 2 is described, which features an efficient palladium-catalyzed cyanation of a 5-chloropyrazinone where zinc acetate suppresses dehalogenation. This synthesis was applied to the preparation of >5 kg of 1 and 2 for clinical studies.

A scalable and robust process was developed for the preparation of pexacerfont (2), a pyrazolotriazine corticotropin-releasing factor receptor 1 antagonist (CRF1). The formation of the core hydroxypyrazolotriazine moiety was achieved through two consecutive cyclizations of a semicarbazide, employing reaction conditions that are significantly milder than those reported in the literature. Further conversion to the key chloropyrazolotriazine intermediate was accomplished through a novel catalytic process using phosphorous oxychloride as the chlorinating agent. The active pharmaceutical ingredient 2 was obtained in >99.5% purity with a 68% overall yield for the six synthetic steps.