tert-Butyldimethylsilyl O-protected chitosan and chitooligosaccharides: useful precursors for N-modifications in common organic solvents

Rúnarsson, Ögmundur Vidar; Malainer, Clemens; Holappa, Jukka; Sigurdsson, Snorri Th.; Másson, Már

doi:10.1016/j.carres.2008.08.014

Cited by 56 publications

(37 citation statements)

References 35 publications

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“…Although the use of such selective protection resulted in higher DS, this led to an increase in the number of synthetic steps, and some modification at unprotected hydroxyl groups can also be observed [21]. Recently, we reported on silyl protected 3,6-di- O - tert -butyldimethylsilylchitosan (diTBDMS-CS) [22,23], which has been utilized in various chemoselective modifications to give products like N -(bromoacetyl)-diTBDMS-chitosan, N -(2-( N , N , N -trialkylammoniumyl)-chitosan, N , N , N -trimethyl chitosan and chitosan derivatives modified by covalent linking of the highly lipophilic photosensitizer, meso -tetraphenylporphyrin [24,25]. The TBDMS-protected precursor enabled the synthesis to be carried out in an organic medium, thereby allowing well controlled and regioselective modification, leading to homogenous products that can be fully characterized by spectroscopy with techniques, such as 1 H-NMR, FT-IR, COSY and HSQC.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Substituent, Degree of Acetylation and Positioning of the Cationic Charge on the Antibacterial Activity of Quaternary Chitosan Derivatives

et al. 2014

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A series of water-soluble cationic chitosan derivatives were prepared by chemoselective functionalization at the amino group of five different parent chitosans having varying degrees of acetylation and molecular weight. The quaternary moieties were introduced at different alkyl spacer lengths from the polymer backbone (C-0, C-2 and C-6) with the aid of 3,6-di-O-tert-butyldimethylsilyl protection of the chitosan backbone, thus allowing full (100%) substitution of the free amino groups. All of the derivatives were characterized using 1H-NMR, 1H-1H COSY and FT-IR spectroscopy, while molecular weight was determined by GPC. Antibacterial activity was investigated against Gram positive S. aureus and Gram negative E. coli. The relationship between structure and activity/toxicity was defined, considering the effect of the cationic group’s structure and its distance from the polymer backbone, as well as the degree of acetylation within a molecular weight range of 7–23 kDa for the final compounds. The N,N,N-trimethyl chitosan with 100% quaternization showed the highest antibacterial activity with moderate cytotoxicity, while increasing the spacer length reduced the activity. Trimethylammoniumyl quaternary ammonium moieties contributed more to activity than 1-pyridiniumyl moieties. In general, no trend in the antibacterial activity of the compounds with increasing molecular weight or degree of acetylation up to 34% was observed.

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Section: Introductionmentioning

confidence: 99%

The Effect of Substituent, Degree of Acetylation and Positioning of the Cationic Charge on the Antibacterial Activity of Quaternary Chitosan Derivatives

et al. 2014

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“…In common organic solvent, tert -Butyldimethylsilyl O-protected COS and chitosan are available precursors for N -modifications [125]. Carboxymethyl-quaternary ammonium oligochitosan (CM-QAOC) could be used as a fluorescent tracing chemical for industrial cooling water treatment since the fluorescence of CM-QAOC was not affected by common phosphorus-containing inorganic and organic water treatment chemicals or N -dodecyl- N , N -dimethyl-benzenemethanaminium chloride but was influenced by metal ions such as Fe 3+ and Cu 2+ from raw water or corrosion products [126].…”

Section: Biological Functions Of Cosmentioning

confidence: 99%

A Review of the Preparation, Analysis and Biological Functions of Chitooligosaccharide

Liang

Sun

Dai

2018

IJMS

122

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Chitooligosaccharide (COS), which is acknowledged for possessing multiple functions, is a kind of low-molecular-weight polymer prepared by degrading chitosan via enzymatic, chemical methods, etc. COS has comprehensive applications in various fields including food, agriculture, pharmacy, clinical therapy, and environmental industries. Besides having excellent properties such as biodegradability, biocompatibility, adsorptive abilities and non-toxicity like chitin and chitosan, COS has better solubility. In addition, COS has strong biological functions including anti-inflammatory, antitumor, immunomodulatory, neuroprotective effects, etc. The present paper has summarized the preparation methods, analytical techniques and biological functions to provide an overall understanding of the application of COS.

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“…The chemoselective synthesis of 3,6‐di‐ O ‐TBDMS chitosan without using common N‐protecting groups was performed by using the mesylate salt of chitosan and TBDMSCl/Im in DMSO (DS of 1.94). It was verified that chitooligomers can only be fully silylated by sequential treatment with TBDMSCl and TBDMSOTf to silylate the sterically hindered secondary alcohol . The 3,6‐ O ‐silyl protection enhances the solubility of chitosan in organic solvents, allowing subsequent chemical modifications.…”

Section: Selective Modificationmentioning

confidence: 99%

“…Thus, several attempts to increase solubility have been addressed through the introduction of different protecting groups into these polymers at the hydroxyl and amino groups. Protection of the hydroxyl groups, for example, has enabled N‐selective modifications, as described by Másson's group …”

Section: Introductionmentioning

confidence: 99%

Selective Modification of Chitin and Chitosan: En Route to Tailored Oligosaccharides

Carvalho

Queda

Santos

et al. 2016

Chemistry An Asian Journal

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Chitin and chitosan are attractive biopolymers with enormous structural possibilities for chemical modification, creating platforms for new chemical entities with a broad scope of applications, ranging from material science to medicine. During the last few years, incredible efforts have been dedicated to the regioselective modification of these biopolymers paving the way for improved properties and tailored activities. Herein, the most recent advances in chitin/chitosan regioselective modification, reaction conditions, selectivity, and the impact on its applications are highlighted. Moreover, the recent focus on chitooligosaccharides, their regioselective and chemoselective functionalization, as well as their role in biological studies, including molecular recognition with several biological targets are also covered.

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tert-Butyldimethylsilyl O-protected chitosan and chitooligosaccharides: useful precursors for N-modifications in common organic solvents

Cited by 56 publications

References 35 publications

The Effect of Substituent, Degree of Acetylation and Positioning of the Cationic Charge on the Antibacterial Activity of Quaternary Chitosan Derivatives

The Effect of Substituent, Degree of Acetylation and Positioning of the Cationic Charge on the Antibacterial Activity of Quaternary Chitosan Derivatives

A Review of the Preparation, Analysis and Biological Functions of Chitooligosaccharide

Selective Modification of Chitin and Chitosan: En Route to Tailored Oligosaccharides

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