Advances in the chemical synthesis of C-pyranosides/furanosides are summarized, covering the literature from 2000 to 2016. The majority of the methods take advantage of the construction of the glycosidic C—C bond. These C-glycosylation methods are categorized herein in terms of the glycosyl donor precursors, which are commonly used in O-glycoside synthesis and are easily accessible to nonspecialists. They include glycosyl halides, glycals, sugar acetates, sugar lactols, sugar lactones, 1,2-anhydro sugars, thioglycosides/sulfoxides/sulfones, selenoglycosides/telluroglycosides, methyl glycosides, and glycosyl imidates/phosphates. Mechanistically, C-glycosylation reactions can involve glycosyl electrophilic/cationic species, anionic species, radical species, or transition-metal complexes, which are discussed as subcategories under each type of sugar precursor. Moreover, intramolecular rearrangements, such as the Claisen rearrangement, Ramberg–Backlund rearrangement, and 1,2-Wittig rearrangement, which usuall...

Recent Advances in the Chemical Synthesis of C-Glycosides

This Review summarizes close to 500 primary publications and surveys published since 2000 about the syntheses and diverse bioactivities of C-glycopyranosyl (het)arenes. A classification of the preparative routes to these synthetic targets according to methodologies and compound categories is provided. Several of these compounds, regardless of their natural or synthetic origin, display antidiabetic properties due to enzyme inhibition (glycogen phosphorylase, protein tyrosine phosphatase 1B) or by inhibiting renal sodium-dependent glucose cotransporter 2 (SGLT2). The latter class of synthetic inhibitors, very recently approved as antihyperglycemic drugs, opens new perspectives in the pharmacological treatment of type 2 diabetes. Various compounds with the C-glycopyranosyl (het)arene motif were subjected to biological studies displaying among others antioxidant, antiviral, antibiotic, antiadhesive, cytotoxic, and glycoenzyme inhibitory effects.

C-Glycopyranosyl Arenes and Hetarenes: Synthetic Methods and Bioactivity Focused on Antidiabetic Potential

Glioma treatment using targeted chemotherapy is still far from satisfactory due to not only the limited accumulation but also the multiple survival mechanisms of glioma cells, including up-regulation of both autophagy and programmed cell death ligand 1 (PD-L1) expression. Herein, we proposed a combined therapeutic regimen based on functional gold nanoparticles (AuNPs)-enabled chemotherapy, autophagy inhibition, and blockade of PD-L1 immune checkpoint. Specifically, the legumain-responsive AuNPs (D&H-A-A&C) could passively target the glioma site and form in situ aggregates in response to legumain, leading to enhanced accumulation of doxorubicin (DOX) and hydroxychloroquine (HCQ) at the glioma site. HCQ could inhibit the DOX-induced cytoprotective autophagy and thus resensitize glioma cells to DOX. Parallelly, inhibiting autophagy could also inhibit the formation of autophagy-related vasculogenic mimicry (VM) by glioma stem cells. In vivo studies demonstrated that D&H-A-A&C possessed promising antiglioma effect. Moreover, cotreatment with anti-PD-L1 antibody was able to neutralize immunosuppressed glioma microenvironment and thus unleash antiglioma immune response. In vivo studies showed D&H-A-A&C plus anti-PD-L1 antibody could further enhance antiglioma effect and efficiently prevent recurrence. The effectiveness of this strategy presents a potential avenue to develop a more effective and more personalized combination therapeutic regimen for glioma patients.

Aggregable Nanoparticles-Enabled Chemotherapy and Autophagy Inhibition Combined with Anti-PD-L1 Antibody for Improved Glioma Treatment.

Up to now, flue-gas desulfurization (FGD) is one of the most effective techniques to control SO2 emission from the combustion of fossil fuels. The conventional technology for FGD poses serious inherent drawbacks such as formation of byproducts and volatilization of solvents. In this work, polyethylene glycol (PEG)-functionalized Lewis basic ionic liquids (ILs) derived from DABCO were proved to be highly efficient absorbents for FGD due to its specific features such as high thermal stability, negligible vapor pressure, high loading capacity. Notably, PEG150MeDABCONTf2 gave an extremely high SO2 capacity (4.38 mol mol−1 IL), even under 0.1 bar SO2 partial pressure (1.01 mol mol−1 IL), presumably owing to the strong SO2-philic characterization of the PEG chain. Furthermore, the absorbed SO2 could be easy to release by just bubbling N2 at room temperature, greatly reducing energy requirement for SO2 desorption. In addition, SO2/CO2 selectivity (110) of PEG150MeDABCONTf2 is two times larger than the non-functionalized imidazolium IL (45). On the other hand, through activation of SO2 with the tertiary nitrogen in the cation, Lewis basic ILs such as PEG150MeDABCOBr proved to be efficient catalysts for the conversion of SO2 to some value-added chemicals such as cyclic sulfites without utilization of any organic solvent or additive. Thus, this protocol would pave the way for the development of technological innovation towards efficient and low energy demanded practical process for SO2 absorption and subsequent transformation.

Highly efficient SO2 absorption/activation and subsequent utilization by polyethylene glycol-functionalized Lewis basic ionic liquids

A binary system consisting of polyethylene glycol (PEG, proton donor)/PEG-functionalized base with suitable basicity was developed for efficient gas desulfurization (GDS) and can be regarded as an alternative approach to circumvent the energy penalty problem in the GDS process. High capacity for SO2 capture up to 4.88 mol of SO2/mol of base was achieved even under low partial pressure of SO2. Furthermore, SO2 desorption runs smoothly under mild conditions (N2, 25 °C) and no significant drop in SO2 absorption was observed after five-successive absorption–desorption cycles. On the other hand, the absorbed SO2 by PEG150MeIm/PEG150, being considered as the activated form of SO2, can be directly transformed into value-added chemicals under mild conditions, thus eliminating the energy penalty for SO2 desorption and simultaneously realizing recycle of the absorbents. Thus, this SO2 capture and utilization (SCU) process offers an alternative way for GDS and potentially enables the SO2 conversion from flue gas to ...

Highly Efficient SO2 Absorption and Its Subsequent Utilization by Weak Base/Polyethylene Glycol Binary System

1,2-Cyclic sulfite and sulfate furanoside diesters: improved syntheses and stability

Development of a potent and selective cell penetrant Legumain inhibitor

Facile access to new C-glycosides and C-glycoside scaffolds incorporating functionalised aromatic moieties

Reactivity of 1,2-cyclic sulfite xylosides towards nucleophiles

We wish to report a simple synthetic procedure, which permits the regiospecific mono-acylation, alkylation and silylation at the 2-position of allyl 4,6-O-benzylidene α-D-glucopyranoside in high yields and which does not require the use of catalysts.

https://www.beilstein-journals.org/bjoc/content/pdf/1860-5397-3-26.pdf

Kerry A. Ness

Papers

1,2-Cyclic sulfite and sulfate furanoside diesters: improved syntheses and stability

Development of a potent and selective cell penetrant Legumain inhibitor

Facile access to new C-glycosides and C-glycoside scaffolds incorporating functionalised aromatic moieties

Reactivity of 1,2-cyclic sulfite xylosides towards nucleophiles

Solvent-controlled regioselective protection of allyl-4,6-benzylidene glucopyranosides