Cyclometalated phenylquinoline rhodium complexes as protein kinase inhibitors

A new metal-containing scaffold for the generation of rhodium(III)-based protein kinase inhibitors is introduced in which the pharmacophore ligand 4-phenylpyrrolo[3,4-c]quinoline-1,3(2H)-dione is designed to form two hydrogen bonds with the hinge region of the ATP-binding site. The phenylquinoline ligand binds to rhodium(III) in a cyclometalated fashion by coordinating to the quinoline nitrogen and forming a covalent bond to a carbon atom of the phenyl substituent. Additional acyclic tridentate ligands were used to control the relative stereochemistry, whereas a chiral proline-derived tridentate ligand was employed for the asymmetric synthesis of single enantiomers. Finally, protein kinase profiling and inhibition data confirmed that the new rhodium(III)-phenylquinoline scaffold is suitable for the generation of selective protein kinase inhibitors.