Potent inhibitor of cyclin dependent kinases (cdks; reported IC50 values are 6 - 45, 14, 16 and 20 nM for cdk2, cdk5, cdk1 and cdk9 respectively). Also inhibits cdk4 and cdk7 in the sub micromolar range. Exhibits antiproliferative activity in human tumor cell lines. Blocks cell cycling at G2-M, S and G1 phases; reduces the proportion of actively cycling cells in vivo. Purity 99%. MW (observed): 371.46