Discovery of pyrrolopyrimidinone derivatives as potent PKMYT1 inhibitors for the treatment of cancer

The protein kinase PKMYT1 is responsible for inhibitory CDK1 phosphorylation, thus playing a central role in regulating the G2/M cell cycle checkpoint. As many cancers have dysfunctional cell cycle checkpoint signaling, PKMYT1 inhibition is emerging as an attractive target in advanced tumors. PKMYT1 inhibitors, however, have encountered difficulties in balancing biological efficacy, on-target specificity, and favorable stability and other drug-like properties. Herein, we report the design and development of pyrrolopyrimidinone derivatives intended to simultaneously restrict molecular conformation and shield a metabolic site in order to optimize stability. Compound 7 demonstrated strong PKMYT1-specific inhibition, a subsequent decrease in CDK1 phosphorylation, and antitumor efficacy in vitro, as well as enhanced metabolic stability, favorable pharmacokinetic and bioavailability properties, and potent antitumor in vivo efficacy. Our findings indicate that compound 7 is a promising PKMYT1 inhibitor for the treatment of advanced cancers with cell cycle defects.