Cell‐Active, Arginine‐Targeting Irreversible Covalent Inhibitors for Non‐Kinases and Kinases

Targeted covalent inhibitors (TCIs) play an essential role in the fields of kinase research and drug discovery. TCI strategies to target more common amino acid side-chains have yet to be demonstrated. Targeting other amino acids would also expand the pharmaceutical industry's toolbox for targeting other tough-to-drug proteins. We report herein a glyoxal-based, arginine-reactive strategy to generate potent and selective small-molecule TCIs of Mcl-1 (an important anti-apoptotic protein) by selectively targeting the conserved arginine (R263) in the protein. We further validated the generality of this strategy by developing glyoxal-based, irreversible covalent inhibitors of AURKA (a cancer-related kinase) that showed exclusive reactivity with a solvent-exposed arginine (R220) of this enzyme. We showed the resulting compounds were potent, selective and cell-active, capable of covalently engaging endogenous AURKA in MV-4-11 cells with long residence time. Finally, we showed the potential application of glyoxal-based TCIs in targeting an acquired drug-resistance mutant of ALK kinase (G1202R).