One-step conversion of unprotected sugars to β-glycosyl azides using 2-chloroimidazolinium salt in aqueous solution

Tanaka, Tomonari; Nagai, Hikaru; Noguchi, Masato; Kobayashi, Atsushi; Shoda, Shin Ichiro

doi:10.1039/b905761g

Cited by 180 publications

(150 citation statements)

References 31 publications

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“…The stereoselective synthesis of the required azide precursors has been reviewed. [3] A recently developed methodology also allows the direct conversion of unprotected sugars to glycosyl azides, [12][13][14] often stereoselectively. The ligation method described herein works reliably well for unprotected β-azides of the gluco, galacto and fuco series.…”

Section: Discussionmentioning

confidence: 99%

Stereoselective Synthesis of N‐Glycosyl Amino Acids by Traceless Staudinger Ligation of Unprotected Glycosyl Azides

2009

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The stereoconservative Staudinger ligation of unprotectedα‐ and β‐glycosyl azides with 2‐(diphenylphosphanyl)‐4‐fluorophenyl esters to afford α‐ and β‐N‐glycosyl amino acids is described. The ligation method works reliably well for unprotected β‐azides of the gluco, galacto and fuco series. Lower yields (ca. 50 %) were obtained with a β‐glucosyl‐N‐acetyl azide. The reaction of an α‐glucosyl azide also led to major improvements compared with the use of non‐fluorinated phosphanes. All the N‐glycosyl amino acid products can be isolated and byproducts removed from the crude reaction mixtures by simple water extraction.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Discussionmentioning

confidence: 99%

Stereoselective Synthesis of N‐Glycosyl Amino Acids by Traceless Staudinger Ligation of Unprotected Glycosyl Azides

2009

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“…-Glycosyl azides were synthesized from free saccharides using DMC and sodium azide in the presence of DIPEA according to literature. [20] N-Propargyl acrylamide was synthesized using acryloyl chloride and propargylamine in the presence of triethylamine according to the literature. [21] AAm was used after recrystallization from chloroform/methanol = 10/3.…”

Section: Methodsmentioning

confidence: 99%

“…Finally, the product was purified by ion-exchange column chromatography (Amberlite IR-120B, previously activated with 1 M NaOH, eluent; H2O) and concentrated under reduced pressure to give a β-glycosyl azide. [18,20] 4.4 Synthesis of glycomonomers Glc2AAm. N-Propargyl acrylamide (200 mg, 1.83 mmol), CuSO45H2O (100 mg, 0.398 mmol), AscNa (158 mg, 0.798 mmol), and TBTA (72 mg, 0.136 mmol) were added to a 50% DMF aqueous solution (6.6 mL) of -maltosyl azide (460 mg, 1.25 mmol), and the resulting mixture was stirred for 3.5 h at room temperature.…”

Section: Synthesis Of -Glycosyl Azidesmentioning

confidence: 99%

“…Glycomonomers with triazole-linked acrylamide (AAm) at the anomeric position were synthesized via direct anomeric azidation of free saccharides and subsequent CuAAC. -Glycosyl azides were directly synthesized from the free maltooligosaccharides maltose (Glc2), maltotriose (Glc3), maltopentaose (Glc5), and maltoheptaose (Glc7) using 2-chloro-1,3-dimethylimidazolinium chloride (DMC), sodium azide, and N,N-diisopropylethylamine (DIPEA) in water at 0 C [20]. The resulting -glycosyl azides were reacted in aqueous dimethylformamide (DMF) at room temperature with N-propargyl acrylamide in the presence of a catalytic amount of copper(II) sulfate pentahydrate (CuSO45H2O), L-ascorbic acid sodium salt (AscNa), and tris[(1-benzyl-1H-1,2,3-triazol-4-yl)-methyl]amine (TBTA).…”

Section: Synthesis Of Glycopolymers From Free Saccharidesmentioning

confidence: 99%

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Synthesis of Glycopolymer Gold Nanoparticles Decorated with Oligosaccharides via a Protecting-group-free Process and Their Specific Recognition by Lectins

Tanaka

Fukumoto

Ishitani

2017

Trans. Mat. Res. Soc. Japan

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Glycopolymers with various pendant oligosaccharides were synthesized from free saccharides without protection of the saccharide hydroxy and carboxy groups. The strategy involved direct anomeric azidation of the free saccharides, copper-catalyzed azide-alkyne cycloaddition, and reversible addition-fragmentation chain transfer polymerization using the glycomonomers and trithiocarbonate derivative as a chain transfer agent. After reducing the trithiocarbonate terminal group on the polymer backbone, the resulting thiol-terminated glycopolymers were immobilized on gold nanoparticles via Au-S bound formation. The glycopolymer-decorated gold nanoparticles in aqueous suspension were specifically recognized by the corresponding lectin, with no measurable nonspecific binding.

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“…The nonasaccharide amine 25 [23] was obtained from a sialoglycopeptide [23b] by enzymatic cleavage followed by anomeric azidation, [24] and reduction (Supporting Information Scheme S7).…”

mentioning

confidence: 99%

Convergent Solid‐Phase Synthesis of N‐Glycopeptides Facilitated by Pseudoprolines at Consensus‐Sequence Ser/Thr Residues

et al. 2012

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Dedicated to Professor Hans Paulsen on the occasion of his 90th birthday N-Glycosylation is an important posttranslational modification of proteins. A carbohydrate is transferred to an asparagine within an Asn-X-Ser/Thr consensus sequence.[1]The study of the biological aspects of N-glycosylation often requires the synthesis of N-glycopeptides, [2] which are accessible by two main approaches. In the sequential mode glycosylamino acid cassettes are used for peptide elongation. After incorporation of larger oligosaccharides the solubility and reactivity of the peptide is affected and side reactions, for example, involving free OH groups [3] complicate further elongation. In the convergent mode (Lansbury aspartylation) [4] the sugar is connected to an aspartate after complete assembly of the peptide (Scheme 1). The main drawback of the convergent mode is the formation of cyclic aspartimides during peptide elongation and sugar coupling; [5] this formation depends on the peptide sequence, [6] and the coupling conditions. [7] We found that a pseudoproline (Ypro) [8] at the consensus-sequence Ser/Thr residue (Asn-X-Ser/Thr(Ypro)) efficiently suppresses the formation of aspartimides in the convergent synthesis of N-glycopeptides on the solid phase.The lack of pure N-glycoproteins for biological studies has stimulated research into their synthesis; these syntheses were carried out mainly by ligation techniques.[9] The required glycopeptides and their thioesters are difficult to obtain as the sugar component interferes with the peptide synthesis. The syntheses of longer glycopeptide thioesters are particularly difficult as they require, for example, additional ligation steps [9f, 10] or segment couplings.[3b] For longer N-glycopeptides the convergent approach provides advantages over the sequential approach, [11] especially as the Lansbury aspartylation [4] has been shown to be efficient also on the solid phase.[12]The undesired aspartimide formation can be avoided by peptide backbone (NH) protection, [13] however, this approach is tedious for residues other than glycine, and causes racemization when coupling backbone-protected dipeptides.[12b] Aspartimide formation during peptide elongation can be reduced by using bulky groups to protect the Asp side chain, [14] for example, the 2-phenylisopropylester (PhiPr); [12a] however, trityl anchors are also cleaved under the reaction conditions for PhiPr removal. Dmab-protected [15] Asp residues are compatible with trityl anchors, but the backbone protection of the neighboring amino acid is required. [13a, 16] To provide complex N-glycopeptide thioesters by solidphase Lansbury aspartylation we compared three Asp-sidechain protecting groups for the Fmoc-SPPS of an interleukin-6 (IL-6) 43-48 hexapeptide. The allyl-protected peptide [17] 6 a showed the highest percentage of aspartimide 7 ai formation (15 %), followed by the Dmab peptide 6 b (8 %), and the PhiPr [12a] peptide 6 c (< 1 %; Scheme 2). As well as the protecting group many factors are known to contribute to aspartim...

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One-step conversion of unprotected sugars to β-glycosyl azides using 2-chloroimidazolinium salt in aqueous solution

Abstract: Various beta-glycosyl azides have been synthesized directly in water by the reaction of unprotected sugars and sodium azide mediated by 2-chloro-1,3-dimethylimidazolinium chloride (DMC).

Cited by 180 publications

References 31 publications

Stereoselective Synthesis of N‐Glycosyl Amino Acids by Traceless Staudinger Ligation of Unprotected Glycosyl Azides

Stereoselective Synthesis of N‐Glycosyl Amino Acids by Traceless Staudinger Ligation of Unprotected Glycosyl Azides

Synthesis of Glycopolymer Gold Nanoparticles Decorated with Oligosaccharides via a Protecting-group-free Process and Their Specific Recognition by Lectins

Convergent Solid‐Phase Synthesis of N‐Glycopeptides Facilitated by Pseudoprolines at Consensus‐Sequence Ser/Thr Residues

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