Evolution of the Thienopyridine Class of Inhibitors of IκB Kinase-β:  Part I:  Hit-to-Lead Strategies

High-throughput screening is routinely employed as a method for the identification of novel hit structures. Large numbers of active compounds are typically procured in this way and must undergo a rigorous validation process. This process is described in detail for a collection of screening hits identified as inhibitors of IκB kinase-β (IKKβ), a key regulatory enzyme in the nuclear factor-κB (NF-κB) pathway. From these studies, a promising hit series was selected. Subsequent lead generation activities included the development of a pharmacophore hypothesis and structure−activity relationship (SAR) for the hit series. This led to the exploration of related scaffolds offering additional opportunities, and the various structural classes were comparatively evaluated for enzyme inhibition, selectivity, and drug-like properties. A novel lead series of thienopyridines was thereby established, and this series advanced into lead optimization for further development.