ABSTRACT
A series of inhibitors for the 90 kDa ribosomal S6 kinase (RSK) based on an 1-oxo-2,3,4,5-tetrahydro-1H-[1,4]diazepino[1,2-a]indole-8-carboxamide scaffold were optimized for cellular potency and kinase selectivity. This led to the identification of compound 24, BIX 02565, an attractive candidate for use in vitro and in vivo to explore the role of RSK as a target for the treatment heart failure.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Indoles/chemistry , Ribosomal Protein S6 Kinases, 90-kDa/antagonists & inhibitors , Ribosomal Protein S6 Kinases, 90-kDa/metabolism , Amides/chemistry , Chemistry, Pharmaceutical/methods , Crystallography, X-Ray/methods , Drug Design , Drug Evaluation, Preclinical/methods , Humans , Inhibitory Concentration 50 , Models, Chemical , Molecular Conformation , Nitrogen/chemistry , Structure-Activity RelationshipABSTRACT
Benzimidazole 1 was identified as a selective inhibitor of ITK by high throughput screening. Hit-to-lead studies defined the SAR at all three substituents. Reversing the amide linkage at C6 led to 16, with a fivefold improvement of potency. This enhancement is rationalized by the conformational preference of the substituent. A model for the binding of the benzimidazoles to the ATP-binding site of ITK is proposed.