1,4,5,6-tetrahydropyrrolo[3,4-c] pyrazoles:: Identification of a potent aurora kinase inhibitor with a favorable antitumor kinase inhibition profile

The optimization of a series of 5-phenylacetyl 1,4,5,6-tetrahydropyrrolo[3,4-c] pyrazole derivatives toward the inhibition of Aurora kinases led to the identification of compound 9d. This is a potent inhibitor of Aurora kinases that also shows low nanomolar potency against additional anticancer kinase targets. Based on its high antiproliferative activity on different cancer cell lines, favorable chemico-physical and pharmacokinetic properties, and high efficacy in in vivo tumor models, compound 9d was ultimately selected for further development.