Design, Synthesis, and Biological Evaluation of 2,4-Diaminopyrimidine Derivatives as Potent CDK7 Inhibitors

Developing selective CDK7 inhibitors has emerged as a promising approach for cancer treatment owing to the critical role of CDK7 in cancer progression. Starting from BTX-A51, a CK1α inhibitor that also targets CDK7 and CDK9, we designed and synthesized a series of 2,4-diaminopyrimidine derivatives as potent CDK7 inhibitors. The representative compound, 22, displayed significant enzymatic inhibitory activity and demonstrated a remarkable selectivity profile against a panel of kinases, including seven CDK subtypes. Modeling studies and molecular dynamics simulations revealed that the sulfone group of 22 significantly enhanced the binding affinity, while the acetyl group contributed to the increased selectivity of CDK7 against CDK9. Compound 22 effectively inhibited the phosphorylation of RNA polymerase II and CDK2 and resulted in G1/S phase cell cycle arrest and apoptosis in MV4-11 cells. It appears to be a promising lead compound for the development of a CDK7 inhibitor for cancer therapy.