Inhibitors of beta-Site Amyloid Precursor Protein Cleaving Enzyme (BACE1): Identification of (S)-7-(2-Fluoropyridin-3-yl)-3-((3-methyloxetan-3-yl)ethynyl)-5'H-spiro[chromeno[2,3-b]pyridine-5,4'-oxazol]-2'-amine (AMG-8718).
Dineen, T.A., Chen, K., Cheng, A.C., Derakhchan, K., Epstein, O., Esmay, J., Hickman, D., Kreiman, C.E., Marx, I.E., Wahl, R.C., Wen, P.H., Weiss, M.M., Whittington, D.A., Wood, S., Fremeau, R.T., White, R.D., Patel, V.F.(2014) J Med Chem 57: 9811-9831
- PubMed: 25363711 
- DOI: https://doi.org/10.1021/jm5012676
- Primary Citation of Related Structures:  
4RCD - PubMed Abstract: 
We have previously shown that the aminooxazoline xanthene scaffold can generate potent and orally efficacious BACE1 inhibitors although certain of these compounds exhibited potential hERG liabilities. In this article, we describe 4-aza substitution on the xanthene core as a means to increase BACE1 potency while reducing hERG binding affinity. Further optimization of the P3 and P2' side chains resulted in the identification of 42 (AMG-8718), a compound with a balanced profile of BACE1 potency, hERG binding affinity, and Pgp recognition. This compound produced robust and sustained reductions of CSF and brain Aβ levels in a rat pharmacodynamic model and exhibited significantly reduced potential for QTc elongation in a cardiovascular safety model.
Organizational Affiliation: 
Departments of Therapeutic Discovery, ‡Neuroscience, §Molecular Structure and Characterization, ∥Pharmacokinetics and Drug Metabolism, and ⊥Comparative Biology and Safety Sciences, Amgen, Inc. , 360 Binney Street, Cambridge, Massachusetts 02142, and One Amgen Center Drive, Thousand Oaks, California 91320, United States.