CK1-IN-2 (compound Nr.4) hydrochloride is a potent CK1 inhibitor with an IC50 values of 123, 19.8, 26.8, 74.3 nM for CK1a, CK1d, CK1e, p38a, respectively[1].
References
[1] Joris De Maeyer, et al. Casein kinase 1 inhibitors for use in the treatment of diseases related to dux4 expression such as muscular dystrophy and cancer. WO2020249717A1.