A pan-CDK inhibitor (IC50s = 3, 1, 1, and 4 nM for CDK1, CDK2, CDK5, and CDK9, respectively) that inhibits DNA synthesis in A2780 ovarian cancer cells (IC50 = 4 nM); 5 mg/kg prevents tumor growth by 50% in an A2780 ovarian carcinoma mouse xenograft model; active against a broad spectrum of human tumor cell lines in vitro (IC50s = 7-17 nM).