Design of Glycopolymers for Controlling the Interactions with Lectins

Carbohydrates are involved in life activities through the interactions with their corresponding proteins (lectins). Pathogen infection and the regulation of cell activity are controlled by the binding between lectins and glycoconjugates on cell surfaces. A deeper understanding of the interactions of glycoconjugates has led to the development of therapeutic and preventive methods for infectious diseases. Glycopolymer is one of the classes of the materials present multiple carbohydrates. The properties of glycopolymers can be tuned through the molecular design of the polymer structures. This review focuses on research over the past decade on the design of glycopolymers with the aim of developing inhibitors against pathogens and manipulator of cellular functions.

Influenza Virus Precision Diagnosis and Continuous Purification Enabled by Neuraminidase-Resistant Glycopolymer-Coated Microbeads

Rapid diagnosis and vaccine development are critical to prevent the threat posed by viruses. However, rapid tests, such as colloidal gold assays, yield false-negative results due to the low quantities of viruses; moreover, conventional virus purification, including ultracentrifugation and nanofiltration, is multistep and time-consuming, which limits laboratory research and commercial development of viral vaccines. A rapid virus enrichment and purification technique will improve clinical diagnosis sensitivity and simplify vaccine production. Hence, we developed the surface-glycosylated microbeads (glycobeads) featuring chemically synthetic glycoclusters and reversible linkers to selectively capture the influenza virus. The surface plasmon resonance (SPR) evaluation indicated broad spectrum affinity of S-linked glycosides to various influenza viruses. The magnetic glycobeads were integrated into clinical rapid diagnosis, leading to a 30-fold lower limit of detection. Additionally, the captured viruses can be released under physiological conditions, delivering purified viruses with >50% recovery and without decreasing their native infectivity. Notably, this glycobead platform will facilitate the sensitive detection and continuous one-step purification of the target virus that contributes to future vaccine production.

Influence of Monomer Structures for Polymeric Multivalent Ligands: Consideration of the Molecular Mobility of Glycopolymers

Molecular mobility is important for interactions of biofunctional polymers with target molecules. Monomer structures for synthetic biofunctional polymers are usually selected based on their compatibility with polymerization systems, whereas the influence of monomer structures on the interaction with target molecules is hardly considered. In this report, we evaluate the correlation between the monomer structures of glycopolymers and their interactions with concanavalin A (ConA) with respect to the molecular mobility. Two types of glycopolymers bearing mannose are synthesized with acrylamide or acrylate monomers. Despite the similar structures, except for amide or ester bonds in the side chains, the acrylate-type glycopolymers exhibit stronger interaction with ConA both in the isothermal titration calorimetry measurement and in a hemagglutination inhibition assay. Characterization of the acrylate-type glycopolymers suggests that the higher binding constant arises from the higher molecular mobility of mannose units, which results from the rotational freedom of ester bonds in their side chains.

Preparation and characterization of glycopolymers with biphenyl spacers via Suzuki coupling reaction

Poly(vinylbiphenyl)s bearing glycoside ligands at the side chains were prepared using the Suzuku coupling reaction. Effects of glycoside reactant concentration, halide species, glycoside species, and catalyst species on the incorporation of glycoside ligand into the polymer were investigated. The obtained glycopolymers exhibited specific binding to proteins corresponding to the glycoside ligands. In addition, the biphenyl spacers formed by the Suzuki coupling reaction in the glycopolymer were fluorescent, whereas the polymer precursor was not.

20 Years of Forging N-Heterocycles from Acrylamides through Domino/Cascade Reactions

Acrylamides are versatile building blocks that are easily obtained from readily available starting materials. During the last 20 years, these valuable substrates bearing a nucleophilic nitrogen atom and an electrophilic double bond have proven to be efficient domino partners, leading to a wide variety of complex aza-heterocycles of synthetic relevance. In this non-exhaustive review, metal-free and metal-triggered reactions followed by an annulation will be presented; these two approaches allow good modulation of the reactivity of the polyvalent acrylamides.

1 Introduction

2 Metal-Free Annulations

2.1 Domino Reactions Triggered by a Michael Addition

2.2 Domino Reactions Triggered by an Aza-Michael Addition

2.3 Domino Processes Triggered by an Acylation Reaction

2.4 Domino Reactions Triggered by a Baylis–Hillman Reaction

2.5 Cycloadditions and Domino Reactions

2.6 Miscellaneous Domino Reactions

3 Metal-Triggered/Mediated Annulations

3.1 Zinc-Promoted Transformations

3.2 Rhodium-Catalyzed Functionalization/Annulation Cascades

3.3 Cobalt-Catalyzed Functionalization/Annulation Cascades

3.4 Ruthenium-Catalyzed Functionalization/Annulation Cascades

3.5 Iron-Catalyzed Functionalization/Annulation Cascades

3.6 Palladium-Catalyzed Functionalization/Annulation Cascades

3.7 Copper-Catalyzed Transformations

3.8 Transition Metals Acting in Tandem in Domino Processes

4 Radical Cascade Reactions

5 Conclusion