Purity >98% by HPLC. LH-846 is a potent and selective inhibitor of casein kinase (CK) 1d (IC50 values are 290 nM, 1.3 MM and 2.5 MM for CK1d, e anda); displays no inhibitory activity at CK2. Inhibits CK1d-dependent phosphorylation and degradation of PER1 protein. LH846 increases circadian period by 10 hours in human U2OS cells.