Homogeneous tosylation of agarose as an approach toward novel functional polysaccharide materials

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Gericke M, Heinze T
Publisher: Pergamon
Publication year: 2015
Journal: Carbohydrate Polymers
Journal acronym: CARBOHYD POLYM
Volume number: 127
Start page: 236
End page: 245
Number of pages: 10
ISSN: 0144-8617
eISSN: 1879-1344


Abstract

The homogeneous tosylation of agarose was studied with respect to the effects of reaction parameters, such as reaction medium, time, and molar ratio, on the reaction course, the degree of substitution (DS) with tosyl/chloro deoxy groups, and the molecular structure. Tosyl agaroses (TOSA) with DStosyl <= 1.81 could be obtained in completely homogeneous reactions by using N,N-dimethylacetamide (DMA)/LiCl or 1,3-dimethyl-2-imidazolidinone (DMI) as solvents. The products were characterized by FT-IR and NMR spectroscopy and it was demonstrated that two types of substitution pattern can be achieved: (i) non-preferential substitution at position 6 of the 1 -> 3-linked beta-D-galactose unit (G-6) and position 2 of the 1 -> 4-linked 3,6-anyhdro-alpha-L-galactose unit (LA-2) and (ii) regioselective tosylation at G-6, depending on whether the reaction is performed with or without LiCl. Finally, the nucleophilic displacement reaction of TOSA was studied using azide and ethylenediamine as representative nucleophiles. Novel deoxy-agarose derivatives were obtained that showed an interesting solubility behavior and will be used for creating functional polysaccharide materials.


Keywords

Agarose, Homogeneous synthesis, NMR spectroscopy, Polysaccharide derivatives, Substituent distribution pattern, Tosylation

Last updated on 2020-30-05 at 03:50