Synthetic Studies on Sialoglycoconjugates. 3: Synthesis of 5-Acetamido-3,5-Dideoxy-l-<i>Arabino</i>-2-Heptulosonic Acid Derivatives and Analogs

Hasegawa, Akira; Ito, Yukiteru; Ishida, Hideyuki; Kiso, Makoto

doi:10.1080/07328308908047997

Cited by 18 publications

(6 citation statements)

References 18 publications

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“…4c,16 Diol 14 was prepared as follows (Scheme 2). The starting a-benzyl sialoside 8 was synthesized from chloride 2 and benzyl alcohol according to the described procedure 17 followed by de-O-acetylation. Treatment of 8 with 2,2-dimethoxypropane and CSA in acetone afforded 8,9-isopropylidene derivative 9 which was selectively benzoylated at O-4 with benzoyl chloride to give monobenzoate 10.…”

Section: Figurementioning

confidence: 99%

Enhanced Sialylating Activity of O-Chloroacetylated 2-Thioethyl Sialosides

Tsvetkov¹,

Nifantiev²

2005

Synlett

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It has been shown that O-chloroacetyl protecting groups enhance significantly sialylating activity of 2-thioethyl sialosides in model reactions of a(2-8)-sialylation. Ethyl 4,7,8,9-tetra-O-chloroacetyl-3,5-dideoxy-2-thio-5-trifluoroacetamido-D-glycero-a-D-galacto-non-2-ulopyranoside that combines electron-withdrawing Ochloroacetyl and N-trifluoroacetyl protecting groups displayed the best reactivity and enabled the most efficient synthesis of the Neu5Aca(2-8)Neu5Ac dimer. The GD 3 tetrasaccharide was synthesized in stepwise manner using this sialyl donor in the key (2-8)-coupling, albeit the yield was noticeably lower than in the model sialylation of monosaccharide acceptors.

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Section: Figurementioning

confidence: 99%

Enhanced Sialylating Activity of O-Chloroacetylated 2-Thioethyl Sialosides

Tsvetkov¹,

Nifantiev²

2005

Synlett

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“…28,29,70, It can be concluded that the application of 2-chloro derivatives of Neu5Ac gives, in general, good yields when coupled with simple or primary sugar alcohols. 99 As a matter of fact, these methods offer the most reliable approach for the synthesis of simple glycosides of Neu5Ac (see, for example, the synthesis of the strategically important OTE glycosides 100 ). More complex glycosides require modern glycosylation methods which will be discussed in the subsequent sections.…”

Section: A 2-halogeno Derivativesmentioning

confidence: 99%

Recent Advances in O-Sialylation

2000

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“…The desired C7-truncated compound 20 was obtained as a minor product but could be readily generated from 21 . Spectroscopic data for 20 were consistent with those previously reported …”

Section: Resultsmentioning

confidence: 99%

Chemoenzymatic Synthesis and Enzymatic Analysis of 8-Modified Cytidine Monophosphate-Sialic Acid and Sialyl Lactose Derivatives

Morley

Withers

2010

J. Am. Chem. Soc.

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The sialic acids found on eukaryotic glycans have remarkably diverse core structures, with a range of modifications at C5, C7, C8 and C9. These carbohydrates have been found to play key roles in cell-cell interactions within eukaryotes and often serve as the initial site of attachment for viruses and bacteria. Consequently simple changes to the structures of the sialic acids can result in profoundly different and often opposing biological effects. Of particular importance are modifications at the 8-position. These include O-acetylation, carried out by an acetyl transferase, and particularly polysialylation, catalyzed by a polysialyltransferase. As part of a structural and mechanistic study of sialyltransferases and polysialyltransferases, access was needed to sialic acid-containing oligosaccharides that are modified at the 8-position of the sialic acid to render this center non-nucleophilic. The free 8-modified sialic acid analogues were synthesized using a concise, divergent chemical synthetic approach, and each was converted to its cytidine monophosphate (CMP) sugar donor form using a bacterial CMP-sialic acid synthetase. The transfer of each of the modified donors to lactose by each of two sialyltransferases was investigated, and kinetic parameters were determined. These yielded insights into the roles of interactions occurring at that position during enzymatic sialyl transfer. A transferase from Campylobacter jejuni was identified as the most suitable for the enzymatic coupling and utilized to synthesize the 8''-modified sialyl lactose trisaccharides in multimilligram amounts.

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Synthetic Studies on Sialoglycoconjugates. 3: Synthesis of 5-Acetamido-3,5-Dideoxy-l-Arabino-2-Heptulosonic Acid Derivatives and Analogs

Cited by 18 publications

References 18 publications

Enhanced Sialylating Activity of O-Chloroacetylated 2-Thioethyl Sialosides

Enhanced Sialylating Activity of O-Chloroacetylated 2-Thioethyl Sialosides

Recent Advances in O-Sialylation

Chemoenzymatic Synthesis and Enzymatic Analysis of 8-Modified Cytidine Monophosphate-Sialic Acid and Sialyl Lactose Derivatives

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