In Pursuit of an Allosteric Human Tropomyosin Kinase A (TrkA) Inhibitor for Chronic Pain.

Human β-nerve growth factor (β-NGF) and its associated receptor, human tropomyosin receptor kinase A (TrkA), have been demonstrated to be key factors in the perception of pain. However, efficacious small molecule therapies targeting the intracellularly located TrkA kinase have not been explored thoroughly for pain management. Herein, we report the pharmacological properties of a selective TrkA allosteric inhibitor, .

Inhibition of cathepsin activity in a cell-based assay by a light-activated ruthenium compound.

Light-activated inhibition of cathepsin activity was demonstrated in a cell-based assay. Inhibitors of cathepsin K, Cbz-Leu-NHCH2 CN (2) and Cbz-Leu-Ser(OBn)-CN (3), were caged within the complexes cis-[Ru(bpy)2 (2)2 ]Cl2 (4) and cis-[Ru(bpy)2 (3)2 ](BF4 )2 (5) (bpy=2,2'-bipyridine) as 1:1 mixtures of Δ and Λ stereoisomers. Complexes 4 and 5 were characterized by (1) H NMR, IR, and UV/Vis spectroscopies and electrospray mass spectrometry.

Cumyl ester as the C-terminal protecting group in the enantioselective alkylation of glycine benzophenone imine.

Cumyl ester is an optimal C-terminal protecting group for glycine benzophenone imine in asymmetric alkylation reactions catalyzed by Cinchona chiral phase-transfer catalysts. High levels of enantioselectivity have been obtained (up to 94% ee) with this substrate, which provides an attractive alternative to the analogous tert-butyl ester. N-terminal imines and the C-terminal esters can be cleaved from alkylation products by hydrogenolysis, while maintaining acid-labile side chain protecting groups.

Light activation of a cysteine protease inhibitor: caging of a peptidomimetic nitrile with Ru(II)(bpy)2.

A novel method for caging protease inhibitors is described. The complex [Ru(II)(bpy)(2)(1)(2)](PF(6))(2) (2) was prepared from the nitrile-based peptidomimetic inhibitor Ac-Phe-NHCH(2)CN (1). (1)H NMR, UV-vis, and IR spectroscopic and mass spectrometric data confirmed that 2 equiv of inhibitor 1 bind to Ru(II) through the nitrile functional group.

A divergent strategy for attaching polypyridyl ligands to peptides.

A divergent method for incorporating polypyridyl ligands into peptides is reported. Three N-Fmoc unnatural amino acids (1-3) that contain varying linkers between the alpha-carbon and a 2-(hydroxymethyl)pyridyl group were synthesized in enantioenriched form. These amino acids were used as anchors for incorporating multidentate ligands onto a peptide chain in a site-specific fashion.