One‐Pot Protection Strategy of Glucosamine to Assemble Building Blocks of Chitosan and Lipid A

Abstract

This investigation describes a one‐pot reaction to prepare a series of building blocks for glycosylation reactions, such as 3‐alcohol glucosamines, fully protected glucosamines, O‐4 and O‐6 alcohol glucosamines. These reactions readily produce not only glycosyl donors and acceptors, but also different glycosyl units that can be changed based on the needs of the experiment. The synthesis of some molecules containing glucosamines, including saccharide chains of glycopeptide (GP) and precursors of lipid A disaccharide backbone, are also described. GP has good selectivity for tumor angiogenesis and this phenomenon makes the GP a potential target drug. Lipid A has recently been adopted as an adjuvant for human vaccines.

Design, Synthesis, and Bioactivity Evaluation of a TF-Based Cancer Vaccine Candidate Using Lipid A Mimetics As a Built-In Adjuvant

“…Specifically, when the amino group was protected by Phth, only the β-configuration product was obtained (Supporting Information, S9). Then, the Phth group was replaced with the Fmoc ( 19 ), which contributed to the formation of α- configuration because of the neighboring group effect. , After the introduction of Fmoc, target product 15 with an α- configuration was obtained in 59% yield from the hydrolysis of thioglycoside 19 .…”

“…Then, the Phth group was replaced with the Fmoc (19), which contributed to the formation of αconfiguration because of the neighboring group effect. 33,45 After the introduction of Fmoc, target product 15 with an αconfiguration was obtained in 59% yield from the hydrolysis of thioglycoside 19.…”

Utilizing a Mild and Effective Catalyst, Alum (KAl(SO4)2⋅12H2O), for Carbohydrate Protection

“…The approach involved testing different catalyst loads and temperatures, and the results are presented in Table 1. To start, the optimization was based on a previously reported PTA‐catalyzed acetylation [3c,24] using glucose 1 a , Ac 2 O as the solvent, and 10 mol % alum (KAl(SO 4 ) 2 ) at room temperature. However, this approach did not yield the desired results.…”

Utilizing Reusable Catalyst Phosphotungstic Acid for the Synthesis of Thioglycoside from Per-O-acetyl Saccharides with Microwave-Assisted and De-O-acetylation with Methanol

“…The molecular diversity of oligosaccharides has attracted considerable attention in the field of glycobiology due to the essential roles it plays in important biological activities such as viral and bacterial infections, cell proliferation, and immune response . However, only a few methods for the synthesis of complex oligosaccharides have been developed, most of which are time consuming and require multiple protection/deprotection steps .…”