Regioselective chlorination of cellulose esters by methanesulfonyl chloride

Gao, Chengzhe; Liu, Shu; Edgar, Kevin J.

doi:10.1016/j.carbpol.2018.03.093

Cited by 27 publications

(15 citation statements)

References 64 publications

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“…The FT-IR spectrum (Figure ) displayed a strong absorption at 2110 cm –1 , characteristic of azide groups. In the 13 C spectrum (Figure S4), a new peak appeared at 49 ppm, which we assigned to azide-bearing C6, , while the former C6–Br 13 C resonance (Figure S3) was absent. Failure to detect any bromide content by elemental analysis in the previous study indicated that azide displacement was quantitative and complete.…”

Section: Results and Discussionmentioning

confidence: 94%

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Efficient Synthesis of Glycosaminoglycan Analogs

Gao

Edgar

2018

Biomacromolecules

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Glycosaminoglycans (GAGs) are among the most complex, biologically active polysaccharides in nature. The complexity of GAGs greatly impedes their synthesis, thus complicating the structure-property studies that are so necessary for us to understand the roles of GAGs in natural processes, in pathogen invasion, and to understand how to develop effective interventions, for example, to prevent undesired GAG hijacking by pathogens. Total synthesis of GAG oligomers from monosaccharide building blocks is useful, but incredibly labor-intensive, expensive, and inefficient. In this study, we report a regiospecific synthetic route to two types of designed GAG analogs by chemical modification of commercially available, inexpensive cellulose acetate. Cellulose acetate was first brominated, followed by azide displacement to introduce azides as the GAG amine precursors. The resulting 6-N cellulose acetate was then saponified to liberate 6-OH groups. Subsequent oxidation of the liberated primary hydroxyl groups to carboxyl groups was smoothly effected by a TEMPO-catalyzed process. Finally, the azides were reduced to amines using an aqueous process, new to polysaccharide chemistry, employing reduction by dithiothreitol (DTT). Alternatively, another process new to polysaccharide chemistry could be employed to convert most of the azides to acetamido groups (mimicking those present, for example, in native hyaluronic acid) by reduction with thioacetic acid. All the intermediates and products were characterized by H NMR,C NMR, and FT-IR spectroscopy. This synthetic route provides access to GAG analogs that will be of great interest for exploring structure-property relationships in various biomedical applications.

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Section: Results and Discussionmentioning

confidence: 94%

“…The azide displacement method was adapted from previous studies. , 6-BrCA320S (1.5 g, 5.582 mmol) was dissolved in 40 mL of DMSO in a 100 mL round-bottom flask. Sodium azide (3 equiv per AGU, 16.74 mmol, 1.09 g) was added to the solution.…”

Section: Methodsmentioning

confidence: 99%

Efficient Synthesis of Glycosaminoglycan Analogs

Gao

Edgar

2018

Biomacromolecules

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“…Cellulose ester refers to the product of esterification reaction between hydroxyl group on the molecular chain of cellulose and acid, acid anhydride, acyl halide under the catalysis of acid [18]. Cellulose esters, as the earliest research and production of cellulose derivatives in cellulose chemistry, are widely used in textile, medicine, coatings, film science, petrochemical industry and other fields [19].…”

Section: Esterification Modification Of Cellulosementioning

confidence: 99%

Research Progress on Chemical Modification and Application of Cellulose: A Review

Zhang

Shen

et al. 2022

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Cellulose is a rich natural polymer material, which has the characteristics of biodegradability, environmental friendliness and good biocompatibility. However, compared with conventional materials, there are some shortcomings in performance, such as intolerance corrosion, limited strength and so on. The chemical modification of cellulose not only retains its own excellent characteristics, but also introduces functional groups to endow it with specific properties. The chemical modification and utilization of cellulose has been the focus of research. In this paper, the latest advances in chemical modification of cellulose, such as esterification, etherification and grafting modification, are introduced. The research and application results of cellulose derivatives in food, wastewater treatment, medicine and papermaking in recent years are reviewed.

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“…NBS/PPh 3 bromination of dextran has not been reported. Recently, chemo- and regioselective chlorination of polysaccharide primary alcohols (methanesulfonyl chloride/ N , N -dimethylformamide) has also been reported …”

Section: Introductionmentioning

confidence: 99%

“…Recently, chemo-and regioselective chlorination of polysaccharide primary alcohols (methanesulfonyl chloride/N,N-dimethylformamide) has also been reported. 27 The Edgar group has previously reported exploitation of Furuhata bromination and its exquisite selectivity to permit the synthesis of comb-like polysaccharide derivatives substituted with complete selectivity at C-6. 28,29 In the case of curdlan, for example, 6-bromo-6-deoxycurdlan and its 2,4-O-diesters were coupled with a series of alkyl amines 26 to afford 6-amino-6deoxycurdlans with complete regioselectivity.…”

Section: ■ Introductionmentioning

confidence: 99%

Regioselective Bromination of the Dextran Nonreducing End Creates a Pathway to Dextran-Based Block Copolymers

Chen¹,

Spiering²,

Mosquera-Giraldo

et al. 2020

Biomacromolecules

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Preparation of polysaccharide-based block copolymers with linear architectures is an important goal, opening up clear application potential and requiring significant advances in polysaccharide regio-and chemoselectivity. Herein we report a simple approach to prepare dextran-based block copolymers. Reaction with N-bromosuccinimide (NBS)/triphenyl phosphine (PPh 3 ) regioselectively brominates the sole primary alcohol of linear, unbranched dextran at C-6 of the nonreducing end monosaccharide. The resulting dextran, monofunctionalized with a terminal C-6 bromide, was coupled with various amine terminated polymers to prepare block copolymers, including dextran-b-poly(ethylene glycol), dextran-b-polystyrene, and dextran-b-poly(N-isopropylacrylamide). These renewable-based block copolymers, prepared in two selective, high-yielding steps from native linear dextran, exhibit various interesting properties. Dextran-b-poly(N-isopropylacrylamide) undergoes thermally induced micellization as revealed by dynamic light scattering (DLS), forming micelles upon exceeding 33 °C. We also observed microphase separation in dextran-bpolystyrene by using small-angle X-ray scattering (SAXS). Overall, this methodology provides a new, highly chemo-and regioselective, versatile route to diverse dextran-based block copolymers with useful properties, enabling drug delivery, compatibilization, and other applications.

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Regioselective chlorination of cellulose esters by methanesulfonyl chloride

Cited by 27 publications

References 64 publications

Efficient Synthesis of Glycosaminoglycan Analogs

Efficient Synthesis of Glycosaminoglycan Analogs

Research Progress on Chemical Modification and Application of Cellulose: A Review

Regioselective Bromination of the Dextran Nonreducing End Creates a Pathway to Dextran-Based Block Copolymers

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