Click Chemistry on Curdlan: A Regioselective and Quantitative Approach to Develop Artificial β-1,3-Glucans with Various Functional Appendages

Hasegawa, Takeshi; Umeda, Masaaki; Numata, Munenori; Fujisawa, Tomohisa; Haraguchi, Shuichi; Sakurai, Kazuo; Shinkai, Seiji

doi:10.1246/cl.2006.82

Cited by 46 publications

(20 citation statements)

References 12 publications

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“…The Cu I -catalysed 1,3-dipolar cycloaddition of azides to monosubstituted alkynes was used in a few cases to modify 6-azido-6-deoxypolysaccharides [37]. It leads selectively to 4-substituted 1,2,3-triazoles, while ca.…”

mentioning

confidence: 99%

2‐Azido‐2‐deoxycellulose: Synthesis and 1,3‐Dipolar Cycloaddition

Zhang

Bernet

Bonnet

et al. 2008

Helvetica Chimica Acta

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Chitosan (1) was prepared by basic hydrolysis of chitin of an average molecular weight of 70000 Da, 1 H-NMR spectra indicating almost complete deacetylation. N-Phthaloylation of 1 yielded the known Nphthaloylchitosan (2), which was tritylated to provide 3a and methoxytritylated to 3b. Dephthaloylation of 3a with NH 2 NH 2 · H 2 O gave the 6-O-tritylated chitosan 4a. Similarly, 3b gave the 6-O-methoxytritylated 4b. CuSO 4 -Catalyzed diazo transfer to 4a yielded 95% of the azide 5a, and uncatalyzed diazo transfer to 4b gave 82% of azide 5b. Further treatment of 5a with CuSO 4 produced 2-azido-2-deoxycellulose (7). Demethoxytritylation of 5b in HCOOH gave 2-azido-2-deoxy-3,6-di-O-formylcellulose (6), which was deformylated to 7. The 1,3-dipolar cycloaddition of 7 to a range of phenyl-, (phenyl)alkyl-, and alkylmonosubstituted alkynes in DMSO in the presence of CuI gave the 1,2,3-triazoles 8 -15 in high yields. 2-Azido-2-deoxycellulose should be available from chitosan by diazo transfer. 1,3-Cycloadditions of 2-azido-2-deoxycellulose to alkynes should introduce 1,2,3-triazolyl side chains into chitosan and formally into cellulose, similarly as it is known for 6-azido-6-deoxypolysaccharides [20] [21] 1 ). In the following, we describe the synthesis of 2-azido-2-deoxycellulose and its reactivity in the 1,3-dipolar cycloaddition to alkynes, leading to new chitin/cellulose derivatives.

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confidence: 99%

2‐Azido‐2‐deoxycellulose: Synthesis and 1,3‐Dipolar Cycloaddition

Zhang

Bernet

Bonnet

et al. 2008

Helvetica Chimica Acta

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“…Triethylamine is one of the most common ones, and such a simple additive is capable of stabilizing the copper(I) centers in a number of applications, 28-30 even for reactions carried out 'on water'. [31][32][33] Other readily available amines have been employed (Figure 1), 34,35 but regrettably, no studies have been conducted to determine the nature of the coordinated species responsible for the catalytic activity, or the influence of the substituents on the nitrogen atom. Unarguably, the most popular amine of this series is the Hünig's base, diisopropylethylamine (DIPEA).…”

Section: Amine Ligandsmentioning

confidence: 99%

The Use of Ligands in Copper-Catalyzed [3+2] Azide-Alkyne Cycloaddition: Clicker than Click Chemistry?

Díez‐González¹

2011

COC

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The last decade has witnessed a tremendous increase of the studies concerning [3+2] cycloaddition reactions of azides and alkynes. The recent discovery of copper(I) species as efficient catalysts for this transformation is at the origin of this true explosion. In contrast with classical thermal reactions, copper catalysis leads to the regioselective formation of 1,4-disubstituted 1,2,3-triazoles in high yields and under simple reaction conditions. This transformation has indeed become the most prominent example of the principles of Click chemistry, postulated in 2001 by Sharpless and co-workers.Despite the ever-increasing interest in this process, the use of ligands in this context remains minor when compared to ligandless systems. Nevertheless, besides overcoming the inherent limitations of ligandless systems, the use of ligands in this context has been shown to increase and, more importantly, modulate the catalytic activity of the metal center. Herein, the catalytic activities of ligated copper systems are reviewed in a way intended inspirational for future developments in this field.

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“…Upon substitution of a cellulose polymer in the 6-position with azide at a degree of substitution of 60-88%, it was possible to modify the overall polymer properties through triazole formation with a range of alkynes. [210][211][212] One of the most significant applications of CuAAC in biopolymer is that of connecting a functional probe with a molecule that carries a particular property. Ligation to azide modified polysaccharides leads to new polysaccharides (e. g. 58, Figure 28) with special properties including saccharide branching attachment of fluorophores, changed solubility and charge, electrochemical and charge transfer properties.…”

Section: Biopolymers and Biopolymer Functionalization By Triazole Ligmentioning

confidence: 99%

“…Ligation to azide modified polysaccharides leads to new polysaccharides (e. g. 58, Figure 28) with special properties including saccharide branching attachment of fluorophores, changed solubility and charge, electrochemical and charge transfer properties. [210][211][212][213] …”

Section: Biopolymers and Biopolymer Functionalization By Triazole Ligmentioning

confidence: 99%

Polymer “Clicking” by CuAAC Reactions

Meldal

2008

Macromol. Rapid Commun.

320

151

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The CuAAC “click” reaction has developed as one of the most useful and widely employed reactions in ligation within polymer chemistry. This is due to the unique properties of the Cu(I) catalysis which renders the reaction quantitative even at low concentrations, orthogonal with other chemistries and extremely robust. The formed triazole on the other hand is of intermediate polarity and chemically and biochemically “invisible”, and the CuAAC provides the ideal “click” reaction for stitching together polymer architectures of unprecedended complexity as was it molecular LEGO. The CuAAC “clicking” in polymer chemistry is increasing exponentially and lead to highly defined polymer materials with novel properties.magnified image

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Click Chemistry on Curdlan: A Regioselective and Quantitative Approach to Develop Artificial β-1,3-Glucans with Various Functional Appendages

Cited by 46 publications

References 12 publications

2‐Azido‐2‐deoxycellulose: Synthesis and 1,3‐Dipolar Cycloaddition

2‐Azido‐2‐deoxycellulose: Synthesis and 1,3‐Dipolar Cycloaddition

The Use of Ligands in Copper-Catalyzed [3+2] Azide-Alkyne Cycloaddition: Clicker than Click Chemistry?

Polymer “Clicking” by CuAAC Reactions

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