Discovery of novel 2-(alkylmorpholin-4-yl)-6-(3-fluoropyridin-4-yl)-pyrimidin-4(3H)-ones as orally-active GSK-3ß inhibitors for Alzheimer's disease.

We herein describe the results of further evolution of GSK-3ß inhibitors for Alzheimer's disease from our promising compounds with in vivo tau phosphorylation inhibitory activity by oral administration. Introduction of a low alkyl group instead of the phenyl group at the 3-position of the morpholine moiety aiming to improve pharmacokinetic profiles resulted in potent low molecular weight GSK-3ß inhibitors with good in vitro pharmacokinetic profiles, which also showed in vivo tau phosphorylation inhibitory activity by oral administration. Effect of the stereochemistry of the alkyl moiety is also discussed using docking models.