Regioselective Glycosylation Method Using Partially Protected Arabino- and Galactofuranosyl Thioglycosides as Key Glycosylating Substrates and Its Application to One-Pot Synthesis of Oligofuranoses

Deng, Li-Min; Liu, Xia; Liang, Xing-Yong; Yang, Jinsong

doi:10.1021/jo300084g

Cited by 24 publications

(24 citation statements)

References 73 publications

(65 reference statements)

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“…In this manuscript, we describe the synthesis of 4-12 through an iterative process. This work extends earlier work focused on the preparation of mycobacterial galactan-related oligosacchrides [14][15][16][17][18][19][20][21][22] and 4-12 represent the largest fragments of this important biomolecule chemically synthesized to date. Furthermore, the systematic approach by which these oligosaccharides were assembled allowed us to probe changes in the chemistry that occurred as…”

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confidence: 74%

Synthesis of a homologous series of galactofuranose-containing mycobacterial arabinogalactan fragments

Joe

Lowary

2016

Can. J. Chem.

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Mycobacteria, including the human pathogen Mycobacterium tuberculosis, the causative agent of tuberculosis, produce a complex cell wall structure made of carbohydrates and lipids. The major structural element of the mycobacterial cell wall is a glycoconjugate called the mycolic acid – arabinogalactan – peptidoglycan (mAGP) complex. Inhibition of mAGP biosynthesis is a proven strategy for developing anti-mycobacterial drugs, and thus, understanding the pathways and enzymes involved in the assembly of this molecule is of interest. In this paper, we describe the chemical synthesis of a panel of nine oligosaccharide fragments (4–12) of the galactan domain of the mAGP complex designed as biosynthetic probes. These structures, ranging in size from a hexasaccharide to a tetradecasaccharide, are potential substrates for two biosynthetic enzymes, GlfT2 and AftA, and represent the largest mycobacterial galactan fragments synthesized to date. The route developed was iterative and provided multimilligram quantities of the target molecules 4–12 in good overall yield.

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confidence: 74%

Synthesis of a homologous series of galactofuranose-containing mycobacterial arabinogalactan fragments

Joe

Lowary

2016

Can. J. Chem.

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“…Examples of the synthesis of internal Galf-containing oligosaccharides have been reported and each synthesis has its advantages and drawbacks. 26,[35][36][37][42][43][44][45][46][47][48][49] The thioglycoside method was employed for the first time in the challenging synthesis of internal Galf-containing oligosaccharides from Mycobacterium tuberculosis as well as in the synthesis of the repeating unit of varianose. 44 More recently, a biotinylated tetra β(1-5)galactofuranoside was also synthesized by this method.…”

Section: Synthetic Strategiesmentioning

confidence: 99%

Synthesis of the O-linked hexasaccharide containing β-d-Galf-(1→2)-β-d-Galf in Trypanosoma cruzi mucins

et al. 2012

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The hexasaccharide β-D-Galp-(1→2)-[β-D-Galp-(1→3)]-β-D-Galp-(1→6)-[β-D-Galf(1→2)-β-D-Galf(1→4)]-D-GlcNAc (1) is the largest carbohydrate structure released as alditol by reductive β-elimination from mucins of some strains of T. cruzi. The terminal β-D-Galp units are sites of sialylation by trans-sialidase which transfers sialic acid from the host to the parasite. Hexasaccharide 1 was synthesized by a [3 + 3]-convergent strategy based on a nitrile assisted glycosylation, using the trichloroacetimidate method. The β-D-Galf-(1→2)-β-D-Galf-D-GlcNAc synthon was sequentially constructed from the reducing end to the non-reducing end employing benzyl α-D-galactofuranoside as starting material for the internal Galf unit. The choice of this novel precursor, obtained in one-reaction step from galactose, allowed the introduction of an orthogonal and participating levulinoyl group at O-2. Thus, the diastereoselective construction of the Galf-β(1→4)-GlcNAc linkage by the trichloroacetimidate method of glycosylation was achieved. The (1)H NMR spectrum of alditol 2 was identical to the product released by β-elimination from the parasite mucin.

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“…A hexasaccharide with the same linkages was synthesized [ 86 ]. The two trisaccharides containing both types of linkages ( Table 3 C & D) were prepared [ 26 , 87 , 88 ] because of their importance as repeating units in the arabinogalactan of M. tuberculosis [ 93 ], but is also present in a polysaccharide extracted from Neosartorya [ 36 ]. Gal f is frequently linked to mannose forming galactomannans.…”

Section: Chemically Synthesized Oligosaccharides Of Antigenic Glycansmentioning

confidence: 99%

Galactofuranose Antigens, a Target for Diagnosis of Fungal Infections in Humans

2017

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The use of biomarkers for the detection of fungal infections is of interest to complement histopathological and culture methods. Since the production of antibodies in immunocompromised patients is scarce, detection of a specific antigen could be effective for early diagnosis. D-Galactofuranose (Galf) is the antigenic epitope in glycoconjugates of several pathogenic fungi. Since Galf is not biosynthesized by mammals, it is an attractive candidate for diagnosis of infection. A monoclonal antibody that recognizes Galf is commercialized for detection of aspergillosis. The linkage of Galf in the natural glycans and the chemical structures of the synthesized Galf-containing oligosaccharides are described in this paper. The oligosaccharides could be used for the synthesis of artificial carbohydrate-based antigens, not enough exploited for diagnosis.

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Regioselective Glycosylation Method Using Partially Protected Arabino- and Galactofuranosyl Thioglycosides as Key Glycosylating Substrates and Its Application to One-Pot Synthesis of Oligofuranoses

Cited by 24 publications

References 73 publications

Synthesis of a homologous series of galactofuranose-containing mycobacterial arabinogalactan fragments

Synthesis of a homologous series of galactofuranose-containing mycobacterial arabinogalactan fragments

Synthesis of the O-linked hexasaccharide containing β-d-Galf-(1→2)-β-d-Galf in Trypanosoma cruzi mucins

Galactofuranose Antigens, a Target for Diagnosis of Fungal Infections in Humans

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