Potent and selective ATP-competitive inhibitor of Chk1 and Chk2 (IC50 vales are 5 nM for both kinases); displays at least >10 fold selectivity over a panel of 164 kinases. Potentiates cytotoxicity of DNA-damaging agents. Active in vivo. Also improves efficiency of CRISPR-Cpf1-mediated genome editing in hPSC lines (2.7-fold at 1 μM). Purity 98%. MW (observed): 398.88