Potent and selective CK1δ and CK1ε inhibitor (IC50 values are 44 and 260 nM, respectively). Exhibits selectivity for CK1δ and CK1ε over a panel of other kinases. Inhibits proliferation of melanoma and breast cancer cell lines in vitro. Also inhibits growth of breast tumor xenografts in mice. Purity 98%. MW (observed): 480.45