Order of Reactivity of OH/NH Groups of Glucosamine Hydrochloride and N-Acetyl Glucosamine Toward Benzylation Using NaH/BnBr in DMF

Inhibition Clathrin Mediated Endocytosis: Pitstop 1 and Pitstop 2 Chimeras

Twenty-five chimera compounds of Pitstop 1 and 2 were synthesised and screened for their ability to block the clathrin terminal domain-amphiphysin protein-protein interaction (NTD-PPI using an ELISA) and clathrin mediated endocytosis (CME) in cells. Library 1 was based on Pitstop 2, but no notable clathrin PPI or in-cell activity was observed. With the Pitstop 1, 16 analogues were produced with 1,8-naphthalic imide core as a foundation. Analogues with methylene spaced linkers and simple amides showed a modest to good range of PPI inhibition (7.6-42.5 μM, naphthyl 39 and 4-nitrophenyl 40 respectively) activity. These data reveal the importance of the naphthalene sulfonate moiety, with no des-SO3 analogue displaying PPI inhibition. This was consistent with the observed analogue docked poses within the clathrin terminal domain Site 1 binding pocket. Further modifications targeted the naphthalene imide moiety, with the installation of 5-Br (45 a), 5-OH (45 c) and 5-propyl ether (45 d) moieties. Among them, the OH 45 c and propyl ether 45 d retained PPI inhibition, with propyl ether 45 d being the most active with a PPI inhibition IC50=7.3 μM. This is 2x more potent than Pitstop 2 and 3x more potent than Pitstop 1.

Iron Trichloride-Mediated Cascade Reaction of Aminosugar Derivatives for the Synthesis of Fused Tetrahydroisoquinoline-Tetrahydrofuran Systems

A method to obtain tetrahydroisoquinolines (THIQs) fused to tetrahydrofuran rings from aminosugar derivatives has been developed. The procedure relies on a key deprotection of benzyl ethers followed by a double-cyclization sequence, using FeCl₃ as the sole reagent. This tandem reaction affords the construction of novel fused polycyclic heterocycles with total stereochemical control.

Comprehensive Rehabilitation Therapy Plus Glucosamine Hydrochloride for Exercise-Induced Knee Injuries and the Effect on Knee Function of Patients

Objective

To assess the application value of comprehensive rehabilitation therapy plus glucosamine hydrochloride for exercise-induced knee injuries and its effect on knee function.

Methods

A total of 96 patients with an exercise-induced knee injury who were admitted to our hospital from February 2019 to February 202 were recruited and assigned at a ratio of 1 : 1 with matched general information to a control group (n = 45) or an experimental group (n = 51). Both groups of patients received comprehensive rehabilitation therapy, and the patients in the experimental group were daily given additional glucosamine hydrochloride tablets for 8 weeks.

Results

The experimental group showed a higher treatment efficacy than the control group (P < 0.001). After the treatment, the VAS scores and C-reactive protein of the two groups showed a decline, with a lower result in the experimental group than in the control group (P < 0.001). The Lysholm knee scores were increased in the two groups after the treatment, and the experimental group had a higher score (P < 0.001). After the treatment, patients of both groups showed reduced five-times-sit-to-stand-test (FTSST) results, with a better outcome obtained in the experimental group (P < 0.001).

Conclusion

Comprehensive rehabilitation therapy plus glucosamine hydrochloride effectively improves the clinical efficacy of exercise-induced knee joint injuries and enhances the knee joint rehabilitation of the patients.

Synthesis of LewisX-O-Core-1 threonine: A building block for O-linked LewisX glycopeptides

LewisX (LeX) is a branched trisaccharide Galβ1→4(Fucα1→3)GlcNAc that is expressed on many cell surface glycoproteins and plays critical roles in innate and adaptive immune responses. However, efficient synthesis of glycopeptides bearing LeX remains a major limitation for structure-function studies of the LeX determinant. Here we report a total synthesis of a LeX pentasaccharide 1 using a regioselective 1-benzenesulfinyl piperidine/triflic anhydride promoted [3 + 2] glycosylation. The presence of an Fmoc-threonine amino acid facilitates incorporation of the pentasaccharide in solid phase peptide synthesis, providing a route to diverse O-linked LeX glycopeptides. The described approach is broadly applicable to the synthesis of a variety of complex glycopeptides containing O-linked LeX or sialyl LewisX (sLeX).

Post-polymerization modification of poly(L-glutamic acid) with D-(+)-glucosamine

Carboxyl functional groups of poly(L-glutamic acid) (PGlu) were modified with a D-(+)-glucosamine (GlcN) by amidation using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) as a coupling reagent. The coupling reaction was performed in aqueous medium without protection of hydroxyl functional groups of D-(+)-glucosamine. Poly(L-glutamic acid) and GlcN functionalized polyglutamates (P(Glu-GlcN)) were thoroughly characterized by 1D and 2D NMR spectroscopy and SEC-MALS to gain detailed information on their structure, composition and molar mass characteristics. The results reveal successful functionalization with GlcN through the amide bond and also to a minor extent through ester bond formation in position 1 of GlcN. In addition, a ratio between the α- and β-form of glucosamine substituent coupled to polyglutamate repeating units as well as the content of residual dimethoxy triazinyl active ester moiety in the samples were evaluated.