AZD7762 is a potent and selective inhibitor of Chk1 with IC50 of 5 nM, being equally potent against Chk2 and less potent against CAM, Yes, Fyn, Lyn, Hck and Lck.

LY2603618 is a highly selective Chk1 inhibitor with potential anti-tumor activity. In a cell-free assay, it shows an IC50 of 7 nM, approximately 100-fold more potent against Chk1 than against any of the other protein kinases evaluated.

SCH 900776 (MK-8776) is a selective and highly potent CHK1 inhibitor with IC50 value of 3nM, modest to CDK2 and Chk2 with much higher IC50 values of 160nM and 1.5uM, respectively.

CHIR-124 is a potent Chk1 inhibitor with IC50 of 0.3 nM with 2,000-fold selectivity against Chk2, 500- to 5,000-fold less activity against CDK2/4 and Cdc2.

PF-477736 is a selective, potent and ATP-competitive Chk1 inhibitor with Ki of 0.49 nM and also inhibits VEGFR2, Aurora-A, FGFR3, Flt3, Fms (CSF1R), Ret and Yes and shows ~100-fold selectivity for Chk1 than Chk2.

CCT245737 is a potent, ATP-competitive CHK1 inhibitor with an IC50 of 30-220 nM.

SAR-020106 is an ATP-competitive, potent, and selective CHK1 inhibitor with an IC (50) of 13.3 nmol/L on the isolated human enzyme. This compound abrogates an etoposide-induced G (2) arrest with an IC (50) of 55 nmol/L in HT29 cells, and significantly enhances the cell killing of gemcitabine and SN38 by 3.0- to 29-fold in several colon tumor lines in vitro and in a p53-dependent fashion.

LY2606368 (Prexasertib) is a selective Chk1 inhibitor with IC50 value <1nM, modest to Chk2 and Rsk with IC50 values of 8nM and <10nM.