ABSTRACT
An imidazole series of cyclin-dependent kinase (CDK) inhibitors has been developed. Protein inhibitor structure determination has provided an understanding of the emerging structure activity trends for the imidazole series. The introduction of a methyl sulfone at the aniline terminus led to a more orally bioavailable CDK inhibitor that was progressed into clinical development.
Subject(s)
Cyclin-Dependent Kinases/antagonists & inhibitors , Imidazoles/chemistry , Aniline Compounds/chemistry , Animals , Cell Cycle Proteins/chemistry , Chemistry, Pharmaceutical/methods , Crystallography, X-Ray/methods , Drug Design , Humans , Hydrogen Bonding , Inhibitory Concentration 50 , Mice , Models, Chemical , Molecular Conformation , Structure-Activity RelationshipABSTRACT
Modification of imidazo[1,2-a]pyridine CDK inhibitors lead to identification of less lipophilic imidazo[1,2-b]pyridazine series of CDK inhibitors. Although several equivalent compounds from these two series have similar structure and show similar CDK activity, the SAR of the two series differs significantly. Protein inhibitor structure determination has confirmed differences in binding mode and given some understanding of these differences in SAR. Potent and selective imidazo[1,2-b]pyridazine inhibitors of CDK2 have been identified, which show >1 microM plasma levels following a 2mg/kg oral dose to mice.
