CDK-IN-9 (compound 24) is a potent CDK inhibitor, also as a molecular glue inducing an interaction between CDK12 and DDB1, with an IC 50 values of 4 nM for CDK2/E. CDK-IN-9 leads to polyubiquitination of cyclin K and its subsequent degradation. CDK-IN-9 induce apoptosis through dephosphorylation of retinoblastoma protein and RNA polymerase II.