A potent, specific ATP-competitive inhibitor of GSK-3β with Ki/IC50 of 38/104 nM; shows no significantly inhibition on CDK2, CDK5 (IC50>100 uM) or 26 other kinases; inhibits tau phosphorylation at a GSK3-specific site (Ser-396) in cells and protects N2A neuroblastoma cells against cell death mediated by inhibition of PI3K/Akt pathway.