Discovery of azabenzimidazole derivatives as potent, selective inhibitors of TBK1/IKKε kinases

The design, synthesis and biological evaluation of a series of azabenzimidazole derivatives as TBK1/IKKε kinase inhibitors are described. Starting from a lead compound 1a, iterative design and SAR exploitation of the scaffold led to analogues with nM enzyme potencies against TBK1/IKKε. These compounds also exhibited excellent cellular activity against TBK1. Further structure-based design to improve selectivity over CDK2 and Aurora B resulted in compounds such as 5b-e. These probe compounds will facilitate study of the complex cancer biology of TBK1 and IKKε.