Purity >98%. LH 846 is a benzothiazole analog that selectively inhibits casein kinase (CK) 1Delta (IC50 = 290 nM). It inhibits CK1e and CK1Alpha at much higher concentrations (IC50 s = 1.3 and 2.5 μM, respectively) but does not inhibit CK2. LH 846 has been shown to inhibit CK1Delta-dependent phosphorylation and degradation of PER1 protein and to lengthen the circadian period in U2OS cells.