Improved Manufacturing Route and Polymorphic Control of a Potent and Selective Anaplastic Lymphoma Kinase (ALK) Inhibitor ASP3026

Our effort toward the process improvement of anaplastic lymphoma kinase (ALK) inhibitor ASP3026 (1) is described. A cost-effective and practical synthesis of 1 was accomplished as a result of the change of starting material from 2,4-dichloro-1,3,5-triazine (6) to cyanuric chloride (9) and late-stage introduction of a highly reactive N-methyl piperazine moiety by reductive amination of intermediate ketone 13. The modified process avoided the challenges with the original synthesis and furnished the several hundred kilograms of high-quality API with high economic efficiency, operability, and reproducibility. Furthermore, a sequence of investigation of polymorphic control in the second-generation synthetic route to obtain the thermodynamically desired, most stable polymorph Form A04 is also discussed.