A Tiny Pocket Packs a Punch: Leveraging Pyridones for the Discovery of CNS-Penetrant Aza-indazole IRAK4 Inhibitors.
Bolduc, P.N., Pfaffenbach, M., Evans, R., Xin, Z., Henry, K.L., Gao, F., Fang, T., Silbereis, J., Vera Rebollar, J., Li, P., Chodaparambil, J.V., Metrick, C., Peterson, E.A.(2024) ACS Med Chem Lett 15: 714-721
- PubMed: 38746903 
- DOI: https://doi.org/10.1021/acsmedchemlett.4c00102
- Primary Citation of Related Structures:  
8TVM, 8TVN - PubMed Abstract: 
We herein report the discovery, synthesis, and evolution of a series of indazoles and azaindazoles as CNS-penetrant IRAK4 inhibitors. Described is the use of structure-based and property-based drug design strategically leveraged to guide the property profile of a key series into a favorable property space while maintaining potency and selectivity. Our rationale that led toward functionalities with potency improvements, CNS-penetration, solubility, and favorable drug-like properties is portrayed. In vivo evaluation of an advanced analogue showed significant, dose-dependent modulation of inflammatory cytokines in a mouse model. In pursuit of incorporating a highly engineered bridged ether that was crucial to metabolic stability in this series, significant synthetic challenges were overcome to enable the preparation of the analogues.
Organizational Affiliation: 
Department of Medicinal Chemistry;Department of Multiple Sclerosis and Immunology;Drug Metabolism and Pharmacokinetics;Physical Biochemistry, Biogen, 225 Binney Street, Cambridge, Massachusetts 02142, United States.