LH-846 is a potent and selective inhibitor of casein kinase (CK) 1δ (IC50 values are 290 nM, 1.3 μM and 2.5 μM for CK1δ, ε andα); displays no inhibitory activity at CK2. Inhibits CK1δ-dependent phosphorylation and degradation of PER1 protein. LH846 increases circadian period by 10 hours in human U2OS cells. MW: 316.81. Purity ≥98% by HPLC