High-Throughput Kinetic Analysis for Target-Directed Covalent Ligand Discovery.

Cysteine-reactive small molecules are used as chemical probes of biological systems and as medicines. Identifying high-quality covalent ligands requires comprehensive kinetic analysis to distinguish selective binders from pan-reactive compounds. Quantitative irreversible tethering (qIT), a general method for screening cysteine-reactive small molecules based upon the maximization of kinetic selectivity, is described.

Efficient and facile synthesis of acrylamide libraries for protein-guided tethering.

A kinetic template-guided tethering (KTGT) strategy has been developed for the site-directed discovery of fragments that bind to defined protein surfaces, where acrylamide-modified fragments can be irreversibly captured in a protein-templated conjugate addition reaction. Herein, an efficient and facile method is reported for the preparation of acrylamide libraries from a diverse range of amine fragments using a solid-supported quaternary amine base.

Synthesis and evaluation of heteroaryl substituted diazaspirocycles as scaffolds to probe the ATP-binding site of protein kinases.

With the success of protein kinase inhibitors as drugs to target cancer, there is a continued need for new kinase inhibitor scaffolds. We have investigated the synthesis and kinase inhibition of new heteroaryl-substituted diazaspirocyclic compounds that mimic ATP. Versatile syntheses of substituted diazaspirocycles through ring-closing metathesis were demonstrated.

Design and evaluation of 3,6-di(hetero)aryl imidazo[1,2-a]pyrazines as inhibitors of checkpoint and other kinases.

A range of 3,6-di(hetero)arylimidazo[1,2-a]pyrazine ATP-competitive inhibitors of CHK1 were developed by scaffold hopping from a weakly active screening hit. Efficient synthetic routes for parallel synthesis were developed to prepare analogues with improved potency and ligand efficiency against CHK1. Kinase profiling showed that the imidazo[1,2-a]pyrazines could inhibit other kinases, including CHK2 and ABL, with equivalent or better potency depending on the pendant substitution.

Identification and characterisation of 2-aminopyridine inhibitors of checkpoint kinase 2.

5-(Hetero)aryl-3-(4-carboxamidophenyl)-2-aminopyridine inhibitors of CHK2 were identified from high throughput screening of a kinase-focussed compound library. Rapid exploration of the hits through straightforward chemistry established structure-activity relationships and a proposed ATP-competitive binding mode which was verified by X-ray crystallography of several analogues bound to CHK2. Variation of the 5-(hetero)aryl substituent identified bicyclic dioxolane and dioxane groups which improved the affinity and the selectivity of the compounds for CHK2 versus CHK1.