Comparative studies on the O-sialylation with four different α/β-oriented (N-acetyl)-5-N,4-O-carbonyl-protected p-toluenethiosialosides as donors

Zhang, Xiaotai; Gu, Zhen-yuan; Xing, Guo‐wen

doi:10.1016/j.carres.2014.02.006

Cited by 20 publications

(11 citation statements)

References 39 publications

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“…286–290 A curious inverse dependence on acceptor concentration in certain sialidation reactions was reported by Xing and coworkers and attributed to a change on supramer constitution. 332 Yet further examples have been provided by Kononov who showed, inter alia, the influence of donor concentration on the stereochemical outcome of the reaction of an arabinofuranosyl bromide with dibutyl phosphate (Scheme 65). 333…”

Section: Use Of Cation Clocks To Determine Molecularitymentioning

confidence: 99%

The Experimental Evidence in Support of Glycosylation Mechanisms at the S_N1–S_N2 Interface

et al. 2018

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A critical review of the state-of-the-art evidence in support of the mechanisms of glycosylation reactions is provided. Factors affecting the stability of putative oxocarbenium ions as intermediates at the S1 end of the mechanistic continuum are first surveyed before the evidence, spectroscopic and indirect, for the existence of such species on the time scale of glycosylation reactions is presented. Current models for diastereoselectivity in nucleophilic attack on oxocarbenium ions are then described. Evidence in support of the intermediacy of activated covalent glycosyl donors is reviewed, before the influences of the structure of the nucleophile, of the solvent, of temperature, and of donor-acceptor hydrogen bonding on the mechanism of glycosylation reactions are surveyed. Studies on the kinetics of glycosylation reactions and the use of kinetic isotope effects for the determination of transition-state structure are presented, before computational models are finally surveyed. The review concludes with a critical appraisal of the state of the art.

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Section: Use Of Cation Clocks To Determine Molecularitymentioning

confidence: 99%

The Experimental Evidence in Support of Glycosylation Mechanisms at the S_N1–S_N2 Interface

et al. 2018

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“…The influence of acceptor concentration in the stereoselectivigty of sialidation reactions has also been commented by Xing and coworkers. 30 …”

Section: Kinetic Studiesmentioning

confidence: 99%

“…The influence of additives such as tetraalkylammonium bromides 4,62 and tetramethylurea 63 on glycosylation reactions has been studied for many years with covalent intermediates isolated and well-characterized in some cases. 64 Recent examples on the study of additives include the addition of sulfides and sulfoxides, which afford stable glycosyl sulfonium and oxysulfonium salts, 30,65–66 and of dimethylformamide and other secondary amides, and even catalytic oxindoles, 67 leading to the formation of glycosyl imidates. 68–69 The additives area has been reviewed recently and as such we will not comment further on it here, 70 but rather we will limit ourselves to counter ions.…”

Section: Counterion and Additive Effectsmentioning

confidence: 99%

A propos of glycosyl cations and the mechanism of chemical glycosylation; the current state of the art

Bohé

Crich

2015

Carbohydrate Research

127

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An overview of recent advances in glycosylation with particular emphasis on mechanism is presented. The mounting evidence for both the existence of glycosyl oxocarbenium ions as fleeting intermediates in some reactions, and the crucial role of the associated in counter ion in others is discussed. The extremes of the SN1 and SN2 manifolds for the glycosylation reaction are bridged by a continuum of mechanisms in which it appears likely that most examples are located.

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“…We synthesized asialic acid derivative (SG1) where sialic acid is attached to glucose at the 6-position (Scheme 1). Briefly,b enzyl 2,3,4-tri-O-benzyl-a/b-d-glucopyranoside (1 a, b)w as synthesized using am odified procedure and reacted with the known N-acetyl-5-N,4-O-carbonyl-protected thiosialoside donor (2) [14] to yield 3 a, b.Exclusive a sialoside was obtained, which was confirmed by NMR spectrosco-py. [14a, 15] Next, at hree-step procedure was performed.…”

Section: Influenza Virus Is Ah Ighly Contagious Virust He Us Centersmentioning

confidence: 96%

Electrochemical Assay to Detect Influenza Viruses and Measure Drug Susceptibility

et al. 2015

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We have designed an electrochemical assay to rapidly diagnose influenza viruses. Exposure of a glucose bearing substrate to influenza viruses or its enzyme, Neuraminidase (NA) releases glucose, which was detected amperometrically. We used two methods to detect released glucose. First, we used a standard glucose blood meter to detect two viral NAs and three influenza strains. We also demonstrated drug susceptibility of two antivirals, Zanamivir and Oseltamivir, using the assay. Second, we used disposable test strips to detect nineteen H1N1 and H3N2 influenza strains using this assay in 1 hour. The limit and range of detection of this first generation assay is 10 2 and 10 2 -10 8 plaque forming units (pfu), respectively. Existing, ubiquitous, user friendly glucose meters can be repurposed to detect influenza viruses.

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Comparative studies on the O-sialylation with four different α/β-oriented (N-acetyl)-5-N,4-O-carbonyl-protected p-toluenethiosialosides as donors

Cited by 20 publications

References 39 publications

The Experimental Evidence in Support of Glycosylation Mechanisms at the S_N1–S_N2 Interface

The Experimental Evidence in Support of Glycosylation Mechanisms at the S_N1–S_N2 Interface

A propos of glycosyl cations and the mechanism of chemical glycosylation; the current state of the art

Electrochemical Assay to Detect Influenza Viruses and Measure Drug Susceptibility

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Comparative studies on the O-sialylation with four different α/β-oriented (N-acetyl)-5-N,4-O-carbonyl-protected p-toluenethiosialosides as donors

Cited by 20 publications

References 39 publications

The Experimental Evidence in Support of Glycosylation Mechanisms at the SN1–SN2 Interface

The Experimental Evidence in Support of Glycosylation Mechanisms at the SN1–SN2 Interface

A propos of glycosyl cations and the mechanism of chemical glycosylation; the current state of the art

Electrochemical Assay to Detect Influenza Viruses and Measure Drug Susceptibility

Contact Info

Product

Resources

About

The Experimental Evidence in Support of Glycosylation Mechanisms at the S_N1–S_N2 Interface

The Experimental Evidence in Support of Glycosylation Mechanisms at the S_N1–S_N2 Interface