Journal of Carbohydrate Chemistry最新文献

Several novel benzimidazolium-based ionic liquids (BzIm ILs) with free and acetyl protected glucopyranoside unit were synthesized and used as ligand for Pd-catalyzed environment-friendly Suzuki reaction. The BzIm ILs with the acetyl protection shows the highest activity, probably because the sugar has a large steric hindrance and acetyl groups can coordinate with Pd. The nuclear magnetic resonance spectra of Pd(OAc)₂/Glc-BzIm ILs free glucopyranoside indicate that Pd-C is formed. The Pd nanoparticles protected by ILs with a size of 5.3 (0.6) nm are considered to be real active species. A series of fluorene core arylfluorene derivatives were prepared with isolated yields above 90%.

Sophora flavescens Ait. is a medicinal herb traditionally used to treat inflammatory diseases. In this study, four polysaccharides, SFNP-1, SFNP-2, SFAP-1, and SFAP-2, were isolated from S. flavescens. Both SFNP-1 and SFNP-2 were (1→4)-linked glucans. SFAP-1 and SFAP-2 were identified as pectin-type polysaccharides containing mainly a homo-galacturanan backbone (as shown). NO release inhibition test revealed that the major polysaccharides, SFAP-1 and SFAP-2, did not have a significant anti-inflammatory effect. This result suggests that the anti-inflammatory effect of S. flavescens may not depend on its polysaccharides.

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Carbohydrates, also known as glycans or sugars are the nature’s most abundant biomolecules. Human breast milk contains soluble oligosaccharides that are involved in the biological recognition process. Oligosaccharides occur in numerous conformational states due to their flexible nature at glycosidic linkages. Molecular dynamics simulation is used to investigate the structural flexibility of glycosidic linkage and intramolecular interactions between molecules. The work focused on human milk oligosaccharide (HMOs), lacto-N-fucopentaose (LNFP) I and II, investigated through MD simulation for 250 ns, and its replicate. Possible conformational models for LNFP I and II were determined and deposited in the open-access database 3DSDSCAR. The structural analysis was carried out for the two HMOs with the CPPTRAJ module.

Aromatic diamines are essential components of polyimide and many other thermosetting polymers. Recent attention has been growing on the threading of cyclodextrins (CDs) onto diamine monomers intended to improve the solubility in water and thermal stability of resultant polymers. The co-precipitation method is often used to isolate inclusion complexes (ICs) of aromatic diamines and other sparingly water-soluble aromatic guest molecules with β-CD. To find the viability of other methods, we studied IC formation between β-CD and some aromatic diamines by mixing in hot water, co-precipitation, and solid-state grinding. ICs formation in water was carried out by solid guest dispersion into the β-CD aqueous solution at 80 °C with high-speed magnetic stirring. In contrast, solid-state grinding was employed by adding a small amount of water to promote IC formation. Thus, ICs prepared by mixing in hot water and solid-state grinding methods were crystallized from water by cooling to 4 °C. Structures of the ICs in solution were confirmed by chemical shifts changes of cavity protons of β-CD in ¹H NMR and the cross-peaks between aromatic protons and cavity protons in ¹H-¹H ROESY NMR. Job’s plot and NMR titration experiments were used to determine the stoichiometric ratio of host and guest in solution.

A cationic gold(I)-catalyzed O-glycosylation method involving the use of glycosyl S-3-butynyl thiocarbonate donors has been developed. It was found that glycosyl S-3-butynyl thiocarbonates are orthogonal to regular phenyl thioglycoside donors. The utilization of this method was demonstrated in the synthesis of a trisaccharide.

A new and sustainable preparation of zwitterionic monoamides of galactaric acid is reported. The protocol consists of an efficient conversion of aldaric acid into the corresponding lactone and its further reaction in the presence of diamines, leading to the formation of the corresponding zwitterionic monoamides in high yields and selectivity. The zwitterions have been used as monomers to obtain the corresponding polyhydroxyamides. The overall protocol has shown a high atom economy, and all the carbon atoms present in the reagents are preserved.

The ratio of counter-regulatory hormones to insulin is increased in diabetes. This causes a change in the activities of the enzymes involved in glycogen metabolism. Thus, it is expected that the structure of glycogen will be changed reversibly in diabetes mellitus. The current research was done to study whether the fractions of glycogen have been changed in streptozotocin (STZ)-induced diabetes in rats. To this end, one group of 10 male rats received a single injection with STZ and were compared with the control group. Liver glycogen fractions were analyzed for the content of carbohydrates, protein, and organic phosphate. Hyperglycemia and clinical signs of diabetes appeared after two days of STZ- injection and continued up to two weeks. In diabetic rats relative to controls, total glycogen decreased by about 39% (24.4 ± 3.0 mg/g wet weight of liver vs. 39.7 ± 2.2, p = 0.001), and the change happened entirely in acid-soluble glycogen (ASG) fraction (19.1 ± 1.7 vs. 33.4 ± 2.2, p = 0.001), while acid-insoluble glycogen (AIG) increased slightly but not significantly (5.5 ± 1.1, vs. 4.5 ± 0.8, p = 0.5). Diabetes was also associated with the change in the content of glycogen protein and the ratio of ASG to AIG. The content of organic phosphate was 181.4 ± 26.3 and 39.2 ± 7.9 µg/g wet weight of liver for ASG and AIG fractions in control rats and had no significant change in diabetes. In conclusion, diabetes is accompanied by the reduction in liver glycogen carbohydrate and protein of total and soluble fraction but the content of organic phosphate has not been affected.

Thiosugars are not only playing important roles in saccharide synthesis but also occur widely in pharmaceutical agents, natural products and S-glycopeptides/proteins, and possess critical biological activities. Many methods have been developed for the syntheses of thiosugars, but most of them adopted saturated-glycosyl donors to give 1-thiosugars only. With the development of olefin-chemistry and transition metal catalysis, numerous protocols of thiosugar synthesis were developed with 1,2-unsaturated-glycosyl donors (glycals) giving different stereoselectivity and regioselectivity. In this review, we have summarized the synthetic methods of thiosugars using glycal donors based on promoters/catalysts, including main-group, transition metal, rare-earth and solid-supported catalysts.

The excellent biocompatibility and unique inclusion capability as well as powerful functionalization capacity of cyclodextrins and their derivatives make them especially attractive for engineering novel functional materials for many applications. There has been increasing interest recently to fabricate supramolecular systems based on cyclodextrin materials. This review focuses on state-of-the-art and recent advances in the construction of cyclodextrin-based assemblies and their practical applications in many fields like gene therapy, chemotherapy, antimicrobial drug delivery, metal extraction, food industry, etc. Supramolecular self-assembly materials based on cyclodextrins are also discussed in this review. The fabrication technologies of supramolecular systems including nanoplatforms and hydrogels as well as their applications in nanomedicine and pharmaceutical sciences are highlighted. In the end, the future directions of this field are discussed.

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