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Synthesis of N,N,N-trimethyl chitosan homopolymer and highly substituted N-alkyl-N,N-dimethyl chitosan derivatives with the aid of di-tert-butyldimethylsilyl chitosan

Benediktsdottir, Berglind E.; Gaware, Vivek S.; Runarsson, Ögmundur LU ; Jonsdottir, Sigriaur; Jensen, Knud J. and Masson, Mar (2011) In Carbohydrate Polymers 86(4). p.1451-1460
Abstract
A highly chemoselective strategy for the synthesis of N,N,N-trimethyl chitosan (TMC) homopolymer and highly substituted N-alkyl-N,N-dimethyl chitosan derivatives was achieved using di-tert-butyldimethylsilyl-3,6-O-chitosan (di-TBDMS chitosan) as a precursor. The influence of different solvents, reagents and other reaction conditions on the reduction, trimethylation and quaternization of these di-TBDMS chitosan derivatives was studied. Products were characterized by NMR after each step. Di-TBDMS chitosan was reacted with methyl iodide in NMP, giving a 100% substituted TMC with the trimethyl group appearing at 3.35 ppm in H-1 NMR spectrum. N-Propyl-, N-butyl- and N-hexyl-N,N-dimethyl chitosan derivatives were synthesized by stepwise... (More)
A highly chemoselective strategy for the synthesis of N,N,N-trimethyl chitosan (TMC) homopolymer and highly substituted N-alkyl-N,N-dimethyl chitosan derivatives was achieved using di-tert-butyldimethylsilyl-3,6-O-chitosan (di-TBDMS chitosan) as a precursor. The influence of different solvents, reagents and other reaction conditions on the reduction, trimethylation and quaternization of these di-TBDMS chitosan derivatives was studied. Products were characterized by NMR after each step. Di-TBDMS chitosan was reacted with methyl iodide in NMP, giving a 100% substituted TMC with the trimethyl group appearing at 3.35 ppm in H-1 NMR spectrum. N-Propyl-, N-butyl- and N-hexyl-N,N-dimethyl chitosan derivatives were synthesized by stepwise reductive alkylation of di-TBDMS chitosan, followed by quaternization with dimethyl sulfate in dichloromethane, giving 65-72% substituted N-alkyl-N,N-dimethyl chitosan derivatives under optimized conditions. Analysis of these water-soluble chitosan derivatives by FT-IR, H-1 NMR, C-13 NMR, H-1-H-1 COSY and H-1-C-13 HSQC NMR enabled detailed structural characterization. All peaks could be assigned to N-modification, showing the selectivity of the di-TBDMS protection. (C) 2011 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Chitosan, tert-Butyldimethylsilyl, Deprotection, Stepwise reductive, alkylation, Quaternary chitosan, Trimethyl chitosan
in
Carbohydrate Polymers
volume
86
issue
4
pages
1451 - 1460
publisher
Elsevier
external identifiers
  • wos:000294941100004
  • scopus:80052024720
ISSN
0144-8617
DOI
10.1016/j.carbpol.2011.06.007
language
English
LU publication?
yes
id
6cadb94f-f8bd-461f-8223-5d2082bbfc96 (old id 2180222)
date added to LUP
2011-10-25 08:57:32
date last changed
2017-04-23 03:12:48
@article{6cadb94f-f8bd-461f-8223-5d2082bbfc96,
  abstract     = {A highly chemoselective strategy for the synthesis of N,N,N-trimethyl chitosan (TMC) homopolymer and highly substituted N-alkyl-N,N-dimethyl chitosan derivatives was achieved using di-tert-butyldimethylsilyl-3,6-O-chitosan (di-TBDMS chitosan) as a precursor. The influence of different solvents, reagents and other reaction conditions on the reduction, trimethylation and quaternization of these di-TBDMS chitosan derivatives was studied. Products were characterized by NMR after each step. Di-TBDMS chitosan was reacted with methyl iodide in NMP, giving a 100% substituted TMC with the trimethyl group appearing at 3.35 ppm in H-1 NMR spectrum. N-Propyl-, N-butyl- and N-hexyl-N,N-dimethyl chitosan derivatives were synthesized by stepwise reductive alkylation of di-TBDMS chitosan, followed by quaternization with dimethyl sulfate in dichloromethane, giving 65-72% substituted N-alkyl-N,N-dimethyl chitosan derivatives under optimized conditions. Analysis of these water-soluble chitosan derivatives by FT-IR, H-1 NMR, C-13 NMR, H-1-H-1 COSY and H-1-C-13 HSQC NMR enabled detailed structural characterization. All peaks could be assigned to N-modification, showing the selectivity of the di-TBDMS protection. (C) 2011 Elsevier Ltd. All rights reserved.},
  author       = {Benediktsdottir, Berglind E. and Gaware, Vivek S. and Runarsson, Ögmundur and Jonsdottir, Sigriaur and Jensen, Knud J. and Masson, Mar},
  issn         = {0144-8617},
  keyword      = {Chitosan,tert-Butyldimethylsilyl,Deprotection,Stepwise reductive,alkylation,Quaternary chitosan,Trimethyl chitosan},
  language     = {eng},
  number       = {4},
  pages        = {1451--1460},
  publisher    = {Elsevier},
  series       = {Carbohydrate Polymers},
  title        = {Synthesis of N,N,N-trimethyl chitosan homopolymer and highly substituted N-alkyl-N,N-dimethyl chitosan derivatives with the aid of di-tert-butyldimethylsilyl chitosan},
  url          = {http://dx.doi.org/10.1016/j.carbpol.2011.06.007},
  volume       = {86},
  year         = {2011},
}