All Sugar Based Cellulose Derivatives Synthesized by Azide–Alkyne Click Chemistry

Abstract

chemically by, for example, glycosylation reactions. [3,4] Cellulose can be converted to the corresponding orthoesters by reaction with acetobromoglucose in presence of triethylamine. [5] However, the methods described so far require the use of hazardous reagents. The copper-catalyzed azide-alkyne cycloaddition was found to be advantageous for the preparation of numerous cellulose derivatives. [6,7] This reaction proceeds under mild conditions and even in aqueous media. In addition to a proof of principle, for example, [8,9] this type of click reaction has been utilized for the synthesis of highlyengineered cellulose derivatives. Dendron-like moieties could be attached to cellulose, [10] where either the azide [11] or the alkyne moiety was attached to the complementarily modified polymer backbone. [12] Moreover, azide group containing cellulose derivative could be crosslinked with propargyl modified cyclodextrin to obtain biocompatible gels. [13] The surface of cellulose fibers was modified as well, for example, by copoly merization of alkyne-containing monomers, [14] by silane chemistry, [15,16] or by tosylation of the paper surface followed by nucleophilic displacement with azide ions. [17] The functionalities attached can possess photomicrobicidal properties [18-20] or increase the strength of pulp fibers. [21] Maltose derivatives bearing N-and O-linked propargyl moieties attached to cellulose by azide-alkyne click chemistry increase the water solubility of the polymer. [22,23] This approach of click chemistry enabled the preparation of cellulose block copolymers by using cellulose derivatives bearing alkyne-or azide groups at position 1 of the reducing end of the oligosaccharide chain. [24] The reactive groups can be introduced regioselectively by, for example, 3-O-azidopropoxypoly(ethylene glycol)-2,6-di-O-thexyldimethylsilyl cellulose [25] or 3-O-propargyl cellulose. [26] In the context of plastic waste including the micro-plastic problems, biobased and biodegradable polymers are highly desirable. In this respect, solubility is an interesting parameter to enhance the biocompability of polymers. Moreover, functional polymers synthesized completely based on renewable resource (polymeric and monomeric carbohydrates) are important in order to save fossil resources. In the present paper the synthesis and structural characterization of cellulose derivatives bearing sugar moieties is reported that impart solubility to the polymer by taking advantages of the click chemistry approach. Cellulose is functionalized with different monosaccharides by the azide-alkyne click chemistry approach. Either azide or alkyne moieties are attached to the cellulose backbone and allowed to react with sugar moieties bearing the opposite clickable groups. Between 16% and 100% of the reactive sites at the polymer can be functionalized with sugar molecules and a clear correlation between steric demand and DS Sugar is observed. The polymers remain soluble in aprotic dipolar media like dimethyl sulfoxide. Products with a sufficient hydroph...

Valorization of Esparto Grass Cellulosic Derivatives for the Development of Promising Energetic Azidodeoxy Biopolymers: Synthesis, Characterization and Isoconversional Thermal Kinetic Analysis

“…After chemical functionalization, an obvious drop in the C6 intensity and a new signal at 52 ppm related to the linked C6-N 3 groups are observed, providing further evidence for the regioselectivity substitution of activated primary OH functions bonded to the C6 carbons with N 3 moieties and confirming the successful chemical structure of the designed azidodeoxy cellulosic samples. These findings agreed well with previous NMR spectra of cellulose and its azidodeoxy derivative prepared from other sources [73,74]. Additionally, it can be deduced from Figure 2(b) that the resonance intensity of the substituted C6 atom increased from AEGC to AEGMCC, which is following Nc assessment and FTIR findings.…”

Clickable polymers accessible through nucleophilic substitution on polysaccharides: A sophisticated route to functional polymers

“…The clickable groups attached to the cellulose (azide-or alkyne moiety) were allowed to react with modified sugar compounds containing the corresponding reactive group. With the modified sugars, up to 100% of the reactive moieties on the polymer backbone could be converted, whereby the conversion rate is dependent on the steric demand of the components (Koschella et al 2020b).…”

Glucose Scavenging with Pectin Hydrazide: A Step toward Designing Innovative, Functional, All‐Sugar‐Based Polymers

“…Until now, complex multistep reactions to yield sugar derivatives ready to react with PS had to be performed. [2] Very recently, a straightforward synthesis could be established yielding reactive hydrazides of pectin of different degrees of methylation and polygalacturonic acid with the controlled conversion of the carboxylic acid groups in a short reaction time.The room temperature protocol applies commercially feasible heterogeneous reaction conditions with very good product yield. The PS hydrazides formed were shown to be nontoxic, well watersoluble, and storage-stable biopolymer derivatives.…”

“…Until now, complex multistep reactions to yield sugar derivatives ready to react with PS had to be performed. [ 2 ]…”