3-Methyl-2-((2S) -2- (4- (3-methyl-1,2,4-oxadiazol-5-yl) phenyl) morpholino) -6- as a tau protein kinase inhibitor (Pyrimidin-4-yl) pyrimidin-4 (3H) -one
A compound represented by the formula (I) or a pharmaceutically acceptable salt thereof for use in the prevention and / or treatment of a disease caused by an abnormal increase in tau protein kinase 1 such as a neurodegenerative disease (eg Alzheimer's disease) .