Low‐valency multivalent iminosugars have recently emerged as promising inhibitors of the therapeutically relevant enzyme β‐glucocerebrosidase (GCase). A new synthetic strategy has been developed to simultaneously build more than one trihydroxypiperidine iminosugar unit onto a polyamine scaffold via double reductive amination (DRA) of a d ‐mannose derived dialdehyde. Five divalent derivatives, using both aliphatic and aromatic diamines and a trivalent compound based on an aromatic scaffold have been synthesized and evaluated as GCase inhibitors. Only oligomers with an aromatic core ( 26 , 31 , and 37 ) strongly inhibit GCase with IC ₅₀ values in the low micromolar range and activity enhancements, when compared to the monovalent counterpart, that confirm the occurrence of a positive multivalent effect. Kinetic analysis for divalent 31 and trivalent 37 revealed a mixed‐type inhibition. To rationalize the unexpected behavior of 37 , an integrated biophysical and computational approach based on STD‐NMR, docking, and MD simulations was employed, allowing to clarify the structural basis for its inhibitory profile and paving the way to the rational design of novel inhibitors able to bridge multiple interaction sites of the target enzyme.

Morquio A syndrome is a lysosomal disorder caused by the deficiency of the lysosomal enzyme N-acetylgalactosamine 6-sulfatase (GALNS, EC 3.1.6.4). Currently, enzyme replacement therapy (ERT) is used to treat Morquio A through the infusion of the recombinant enzyme VIMIZIM^® (elosulfase alfa, BioMarin). Unfortunately, the recombinant enzyme exhibits low conformational stability in vivo. A promising approach to address this issue is the coadministration of recombinant human GALNS (rhGALNS) with a pharmacological chaperone (PC), a molecule that selectively binds to the misfolded protein, stabilizes its conformation, and assists in the restoration of the impaired function. We report in this work the synthesis of a library of multivalent glycomimetics exploiting the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction between several dendrimeric scaffolds armed with terminal alkynes and azido ending iminosugars of different structures (pyrrolidines, piperidines, and pyrrolizidines) or simple azido ending carbohydrates as bioactive units. The biological evaluation identified pyrrolidine-based nonavalent dendrimers 1 and 36 as the most promising compounds, able both to bind the native enzyme with IC₅₀ in the micromolar range and to act as enzyme stabilizers toward rhGALNS in a thermal denaturation study, thus identifying promising compounds for a combined PC/ERT therapy.

1,3-Dipolar cycloadditions on nitrone dipoles are key reactions to access five-membered heterocycles, which are useful intermediates in the synthesis of biologically relevant glycomimetics. The good atomic balance and high stereoselectivity characteristic of such reactions make them good candidates for the development of green protocols. In the present work, these features were maximized by avoiding the use of organic solvents and considering starting materials derived from biomass. Reactions involving (acyclic and cyclic) carbohydrate-derived nitrones as dipoles and levoglucosenone as dipolarophile were considered. Performing selected 1,3-dipolar cycloadditions in neat conditions showed reduced reaction times, maintaining similar selectivity and yields with respect to the classical protocols. The use of microwave irradiation and orbital shaking were also exploited to increase the sustainability of the synthetic protocols. The collected results highlight the potential of solvent-free 1,3-dipolar cycloadditions in the design of efficient synthetic routes according to green chemistry principles, such as prevention, atom economy, safer solvents and auxiliaries, and use of renewable feedstocks.

The incorporation of fluorine into bioactive molecules is a widely employed strategy for tuning molecular recognition and pharmacological properties. The enzyme β‐glucocerebrosidase (GCase), whose deficiency causes Gaucher disease and represents a major genetic risk factor for Parkinson disease, is emerging as a key therapeutic target for both pathologies. We report the synthesis and biological evaluation toward GCase of a small collection of fluorinated iminosugars, together with some non‐fluorinated novel control compounds. Diethylaminosulfur trifluoride (DAST)‐mediated deoxyfluorination of suitably protected piperidine intermediates afforded the corresponding fluorinated derivatives. Fluorination proceeded with retention of configuration and, if an alkyl chain at C‐2 is present, induced unexpected stereoselective ring contraction to fluorinated pyrrolidines. Biological evaluation, including enzyme inhibition assays and ex vivo studies in Gaucher disease fibroblasts, revealed distinct behaviors. Fluorination generally enhanced GCase inhibitory potency provided that an alkyl chain was present, whereas restoration of GCase activity in mutant cells depended more subtly on the overall piperidine substitution pattern and was favored by the presence of a trifluoromethyl group in the N ‐alkyl chain. Overall, this study identified new high‐affinity GCase ligands, including a potent fluorinated piperidine, a fluorinated pyrrolidine generated through the ring‐contraction process, and a trifluoromethyl analog retaining the ability to restore GCase activity in Gaucher disease fibroblasts.