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Glycoconjugate vaccines are based on chemical conjugation of pathogen‐associated carbohydrates with immunogenic carrier proteins and are considered a very cost‐effective way to prevent infections. Most of the licensed glycoconjugate vaccines are composed of saccharide antigens extracted from bacterial sources. However, synthetic oligosaccharide antigens have become a promising alternative to natural polysaccharides with the advantage of being well‐defined structures providing homogeneous conjugates. Haemophilus influenzae (Hi) is responsible for a number of severe diseases. In recent years, an increasing rate of invasive infections caused by Hi serotype a (Hia) raised some concern, because no vaccine targeting Hia is currently available. The capsular polysaccharide (CPS) of Hia is constituted by phosphodiester‐linked 4‐β‐d‐glucose‐(1→4)‐d‐ribitol‐5‐(PO4→) repeating units and is the antigen for protein‐conjugated polysaccharide vaccines. To investigate the antigenic potential of the CPS from Hia, we synthesized related saccharide fragments containing up to five repeating units. Following the synthetic optimization of the needed disaccharide building blocks, they were assembled using the phosphoramidite approach for the installation of the phosphodiester linkages. The resulting CPS‐based Hia oligomers were conjugated to CRM197 carrier protein and evaluated in vivo for their immunogenic potential, showing that all glycoconjugates were capable of raising antibodies recognizing Hia synthetic fragments. [ABSTRACT FROM AUTHOR]

Ultra‐small gold nanoparticles (UAuNPs) are extremely interesting for applications in nanomedicine thanks to their good stability, biocompatibility, long circulation time and efficient clearance pathways. UAuNPs engineered with glycans (Glyco‐UAuNPs) emerged as excellent platforms for many applications since the multiple copies of glycans can mimic the multivalent effect of glycoside clusters. Herein, we unravel a straightforward photo‐induced synthesis of Glyco‐UAuNPs based on a reliable and robust microfluidic approach. The synthesis occurs at room temperature avoiding the use of any further chemical reductant, templating agents or co‐solvents. Exploiting 1H NMR spectroscopy, we showed that the amount of thiol‐ligand exposed on the UAuNPs is linearly correlated to the ligand concentration in the initial mixture. The results pave the way towards the development of a programmable synthetic approach, enabling an accurate design of the engineered UAuNPs or smart hybrid nano‐systems. [ABSTRACT FROM AUTHOR]

Vaccination is one of the greatest achievements in biomedical research preventing death and morbidity in many infectious diseases through the induction of pathogen‐specific humoral and cellular immune responses. Currently, no effective vaccines are available for pathogens with a highly variable antigenic load, such as the human immunodeficiency virus or to induce cellular T‐cell immunity in the fight against cancer. The recent SARS‐CoV‐2 outbreak has reinforced the relevance of designing smart therapeutic vaccine modalities to ensure public health. Indeed, academic and private companies have ongoing joint efforts to develop novel vaccine prototypes for this virus. Many pathogens are covered by a dense glycan‐coat, which form an attractive target for vaccine development. Moreover, many tumor types are characterized by altered glycosylation profiles that are known as "tumor‐associated carbohydrate antigens". Unfortunately, glycans do not provoke a vigorous immune response and generally serve as T‐cell‐independent antigens, not eliciting protective immunoglobulin G responses nor inducing immunological memory. A close and continuous crosstalk between glycochemists and glycoimmunologists is essential for the successful development of efficient immune modulators. It is clear that this is a key point for the discovery of novel approaches, which could significantly improve our understanding of the immune system. In this review, we discuss the latest advancements in development of vaccines against glycan epitopes to gain selective immune responses and to provide an overview on the role of different immunogenic constructs in improving glycovaccine efficacy. [ABSTRACT FROM AUTHOR]

The glycosylation with trichloroacetimides derived from different glycopyranoses bearing a nonparticipating group at C-2 was explored in different ionic liquids as solvents. The stereoselectivity was significantly affected by the reaction media and by the anomeric configuration.

The article titled "Front Cover: HPLC‐Based Automated Synthesis and Purification of Carbohydrates" discusses the development of a new HPLC‐based automated synthesizer (HPLC‐A) that can synthesize and purify carbohydrates. The cover art illustrates the automated process, where the operator loads starting materials and initiates the sequence. The synthesized and purified product is then collected in test tubes. The article provides more information on this research, conducted by Gustavo A. Kashiwagi, A. V. Demchenko, and their colleagues. [Extracted from the article]

A novel pathway of synthesizing C-glycosaminosides was developed through regioselective deprotection of the hydroxyl group at C-2 of alpha- and beta-C-glucosyl-2-propenes. The design featured the late amination of C-glucosides with the hydroxyl group at selectively deprotected C-2. Deprotection of C-2 of alpha- and beta-1-{2',3',4',6'-tetra-omicron-benzyl- D-glucopyranosyl}-2-propenes was followed by conversion into alpha- and beta-C-glycosides of glucosamine and mannosamine.

The introduction of the amino function in the molecule after the introduction of the phosphono function is an effective strategy for the stereoselective synthesis of isosteric phosphono analogs of N-acetyl-alpha-D-glucosamine 1-phosphate and N-acetyl-alpha-D-mannosamine 1-phosphate. This method first produces an alpha-C-glucopyranoside having a deprotected hydroxyl group at C-2. It yields two isomers of N-acetyl-alpha-D-glucosamine 1-phosphate alternatively in a stereoselective way.

The reaction of 3,4, 6-tri-O-benzyl-1-deoxy-D-arabino-hexulofuranose with BF3.OEt2 in acetonitrile results in the formation of a C-disaccharide. Similarly, the reactions of the enitols, 2,5-anhydro-3,4,6-tri-O-benzyl-1-deoxy-D-arabino-hex-1-enitol and 2, 6-anhydro-3,4,5,7-tetra-O-benzyl-1-deoxy-D-gluco-hept-1-enitol, with the same preparation form C-disaccharides in 96% and 66% yields, respectively. The enitol reaction involves the stereoselective enol ether function attack on the oxonium ion of another molecule of enol ether.