Novel glucopyranoside C2-derived 1,2,3-triazoles displaying selective inhibition of O-GlcNAcase (OGA).

O-GlcNAcylation or O-GlcNAc modification is a post-translational modification of several proteins responsible for fundamental cellular processes. Dysregulation of the O-GlcNAc pathway has been linked to the etiology of several diseases such as neurodegenerative and cardiovascular diseases, type 2 diabetes and cancer. O-GlcNAcase (OGA) catalyzes the removal of O-GlcNAc from the modified proteins and several carbohydrate-based OGA inhibitors have been synthesized to understand the role of O-GlcNAc-modified proteins in physiological and pathological conditions. However, many of the inhibitors lack selectivity for OGA over lysosomal hexosaminidases A and B. Aiming the selectively inhibition of OGA, we propose herein the synthesis of twelve novel glucopyranoside derivatives exploring the bioisosteric replacement of the GlcNAc 2-acetamide group by 1,4-disubstituted 1,2,3-triazole ring, bearing a variety of central chains with different shapes. Compounds were readily prepared through "Copper(I) Catalyzed Azide/Alkyne Cycloaddition" (CuAAC) reaction between a sugar azide and different terminal alkynes. Initial Western Blot analyses and further inhibitory assays proved that compounds 6a (IC50 = 0.50 ± 0.02 µM, OGA), 6k (IC50 = 0.52 ± 0.01 µM, OGA) and 6l (IC50 = 0.72 ± 0.02 µM, OGA) were the most potent and selective compounds of the series. Structure-activity relationship analyses and molecular docking simulations demonstrated that the bridge of two-carbon atoms between the C-4 position of the triazole and the phenyl ring (6a), which may be replaced by heteroatoms such as N (6k) or O (6l), is fundamental for accommodation and inhibition within OGA catalytic pocket.