Partial or total silylation of dextran with hexamethyldisilazane

Nouvel, Cécile; Ydens, Isabelle; Degée, Philippe; Dubois, Philippe; Dellacherie, Édith; Six, Jean‐Luc

doi:10.1016/s0032-3861(01)00778-9

Cited by 49 publications

(73 citation statements)

References 21 publications

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“…1). A similar procedure was proposed by Nouvel et al [15] for the silylation of starch. Here, the addition of co-solvents (toluene/ THF) led to an increase in the DS.…”

Section: Effect Of the Addition Of Toluene As A Cosolventmentioning

confidence: 84%

Synthesis of Higher Fatty Acid Starch Esters using Vinyl Laurate and Stearate as Reactants

et al. 2008

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This paper describes the synthesis of long-chain fatty esters of corn starch (starch laurate and starch stearate) with a broad range in degree of substitution (DS = 0.2422.96). The fatty esters were prepared by reacting the starch with vinyl laurate or vinyl stearate in the presence of basic catalysts (Na 2 HPO 4 , K 2 CO 3 , and Na acetate) in DMSO at 1107C. The yellowish products were characterized by 1 H-, 13 C-NMR and FT-IR. The DS of the products is a function of the carbon number of the fatty acid chain, vinyl ester to starch ratio and the type of catalyst. When performing the reactions using Na 2 HPO 4 as the catalyst, the DS for the starch laurate compounds is higher than for the corresponding starch stearates. For low vinyl ester to starch ratios, an increase in the vinyl ester concentration leads to higher product DS values. At higher ratios, the DS decreases, presumably due to a reduction of the polarity of the reaction medium. K 2 CO 3 and Na acetate are superior catalysts with respect to activity compared to Na 2 HPO 4 and products with DS values close to 3 were obtained.

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“…1). A similar procedure was proposed by Nouvel et al [15] for the silylation of starch. Here, the addition of co-solvents (toluene/ THF) led to an increase in the DS.…”

Section: Effect Of the Addition Of Toluene As A Cosolventmentioning

confidence: 84%

Synthesis of Higher Fatty Acid Starch Esters using Vinyl Laurate and Stearate as Reactants

et al. 2008

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“…Dex-g-PCLs were synthesized according to an original and controlled three-step procedure recently reported by us and illustrated in Scheme 1 [27,28]. Macromolecular characteristics of the Dex-g-PCL graft copolymers used in the present study are shown in Tab.…”

Section: Methodsmentioning

confidence: 99%

“…Dextran-g-poly(ε-caprolactone) copolymer (Dex x -g-y PCL z ) synthesis [27,28] The first step consisted of the partial reversible silylation of dextran hydroxyl groups in order to control and limit the number of free hydroxyl groups and to facilitate polysaccharide solubilization in low polar organic solvents suitable to perform the controlled ring-opening polymerization (ROP) of ε-caprolactone (CL). We showed that high silylation yields could be reached without any degradation of dextran by using hexamethyldisilazane in dimethyl sulfoxide (DMSO) while hydroxyl groups located on the third and fourth carbon atoms of glucose repeating units were by far less reactive [30][31].…”

Section: Methodsmentioning

confidence: 99%

“…1 shows the main macromolecular characteristics of the investigated dextran-gpoly(ε-caprolactone) graft copolymers, Dex x -g-y PCL z , where x and z denote dextran and poly(ε-caprolactone) (PCL) number-average molar masses (in kg/mol), respectively, and y denotes the average number of PCL grafts per 100 glucose units. These amphiphilic and biodegradable graft copolymers were synthesized according to a recently reported three-step procedure illustrated in Scheme 1 [27][28]30]. The solubility of the so-formed Dex x -g-y PCL z graft copolymers was shown to strongly depend on the relative content in PCL grafts, i.e., the weight fraction in PCL (F wPCL ).…”

Section: Macromolecular Characteristics Of Studied Dextran-g-poly(ε-cmentioning

confidence: 99%

“…The present paper aims at reporting on the exclusive use of amphiphilic, biodegradable poly(ε-caprolactone)-grafted dextran (Dex-g-PCL) enriched in hydrophobic poly(ε-caprolactone) (PCL) for preparing surfactant-free nanoparticles through the nanoprecipitation technique. Purposely, several well-defined Dex-g-PCL compositions were synthesized according to a three-step procedure already reported by us and depicted in Scheme 1 [27,28]. Beside their macromolecular characterization, the interfacial properties of these amphiphilic graft copolymers were studied by the pendant drop method, as well as the mean diameter and size distribution of the soformed nanoparticles by using dynamic light scattering.…”

Section: Introductionmentioning

confidence: 99%

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‘Surfactant-free’ stable nanoparticles from biodegradable and amphiphilic poly(ε-caprolactone)-grafted dextran copolymers

et al. 2005

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A variety of poly(ε-caprolactone)-grafted dextran copolymers were synthesized with a controlled architecture through a three-step procedure: partial protection of the dextran hydroxyl groups by silylation, ring-opening polymerization of ε-caprolactone initiated from remaining free hydroxyl groups on partially silylated dextran, and silyl ether deprotection under mild conditions. The potential of these amphiphilic grafted copolymers as surfactants was investigated by water/toluene interfacial tension measurements. Since each copolymer showed noticeable surfactant properties, their ability to form 'surfactant-free' nanoparticles was evaluated using the nanoprecipitation method. It was found that remarkably stable core (polyester) -shell (polysaccharide) nanoparticles with a mean diameter around 200 nm were formed.

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Modified Natural Polysaccharides as Nanoparticulate Drug Delivery Devices

Bhaw‐Luximon

2010

Engineered Carbohydrate‐Based Materials for Biomedical Applications

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Partial or total silylation of dextran with hexamethyldisilazane

Cited by 49 publications

References 21 publications

Synthesis of Higher Fatty Acid Starch Esters using Vinyl Laurate and Stearate as Reactants

Synthesis of Higher Fatty Acid Starch Esters using Vinyl Laurate and Stearate as Reactants

‘Surfactant-free’ stable nanoparticles from biodegradable and amphiphilic poly(ε-caprolactone)-grafted dextran copolymers

Modified Natural Polysaccharides as Nanoparticulate Drug Delivery Devices

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