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Hyper-branched chitosan or hyper-branched glycol chitosan and preparation method thereof

A technology for ethylene glycol chitosan and chitosan transformation is applied in the field of preparing chitosan, which can solve the problems of no reactivity, and chitosan has not yet been found, and achieves few reaction steps, mild reaction conditions and simple operation. Effect

Inactive Publication Date: 2007-10-24
INST OF CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the high molecular weight chitin is insoluble in water, the side chains of the branched chitosan obtained by them are also very short (up to 6 sugar rings), and the amino groups on the side chain chitin are not acetylated due to being acetylated. reactive
In addition, the modification of chitosan by the above-mentioned grafting method can only obtain a comb-like polymer structure rather than a hyperbranched structure (Hitoshi Sashiwa, Sei-ichi Aiba, "Chemically modified chitin and chitosan as biomaterials", Prog. Polym. Sci ., 2004, 29, 887-908)
At present, there is no report about the preparation of chitosan or its derivatives with hyperbranched structure

Method used

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  • Hyper-branched chitosan or hyper-branched glycol chitosan and preparation method thereof
  • Hyper-branched chitosan or hyper-branched glycol chitosan and preparation method thereof
  • Hyper-branched chitosan or hyper-branched glycol chitosan and preparation method thereof

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Embodiment 1

[0032] Embodiment 1. The preparation of hyperbranched ethylene glycol chitosan

[0033] Ethylene glycol chitosan (Mw = 250 kDa, GPC / light scattering method) was dissolved in 0.2M acetic acid. Add NaNO equivalent to 5% of amino moles under high-speed stirring at 0~4°C 2 Aqueous solution, continue to react at 0 ~ 4 ℃ for 15 hours, then use 3 times the volume of acetone to precipitate. The precipitate was washed several times with acetone and methanol and then dried in vacuum. Obtain the ethylene glycol chitosan that low molecular weight has aldehyde end group after drying, its weight-average molecular weight is 5500 (GPC / light scattering method), and its nuclear magnetic resonance spectrum is shown in Fig. 2, wherein the peak at chemical shift 5.05 place is Aldehyde H. The low molecular weight ethylene glycol chitosan (Mw=5500) degraded by the above nitrous acid was dissolved in 0.1M acetic acid aqueous solution (5mg / mL), stirred at 25°C for 1 hour, then added dropwise with 0...

Embodiment 2

[0034] Embodiment 2. The preparation of hyperbranched chitosan

[0035] 50g of chitosan was dissolved in 1000mL of 5% acetic acid aqueous solution and cooled to 0-4°C. 5gNaNO 2 Dissolve in 50mL of water, add the above chitosan solution dropwise, react at 0-4°C for 9 hours, add concentrated NaOH aqueous solution until all the precipitates are precipitated, filter, wash with methanol and water for several times, and vacuum-dry the obtained product with aldehyde groups. based low molecular weight chitosan. The product (Mw=2300, Mw / Mn=1.5, GPC / light scattering method) of low molecular weight chitosan after methanol precipitation and fractionation was dissolved in 0.1M acetic acid (2mg / mL), stirred at 10°C for 1 hour, and then added dropwise with 0.1 M NaOH in water to pH 5.5. After continuing to stir for 2 hours, add NaCNBH equivalent to 1.0 times the mole number of aldehyde groups 3 , reacted at 10°C for 24 hours and then added the same amount of NaCNBH 3 , continue to react...

Embodiment 3

[0036] The preparation of the hyperbranched chitosan of embodiment 3.quaternary amination

[0037] 5g of chitosan was dissolved in 50mL of 0.2M acetic acid aqueous solution and cooled to 0-4°C. 0.15gNaNO 2 Dissolve in 1mL of water, add the above chitosan solution dropwise, react at 0-4°C for 15 hours, add concentrated NaOH until all the precipitates are precipitated, filter, wash with methanol and water several times, and vacuum-dry to obtain the product with aldehyde end groups Low molecular weight chitosan (Mw=3700, GPC / light scattering method). The obtained low-molecular-weight chitosan was dissolved in 0.1M acetic acid (2 mg / mL), stirred at 60°C for 1 hour, and then 0.1M NaOH aqueous solution was added dropwise until the pH was 5.0. After continuing to stir for 2 hours, add NaCNBH equivalent to 2.0 times the mole number of aldehyde groups 3 , reacted at 60°C for 72 hours. During the control pH value is not higher than 6.0. After the reaction was completed, concentrate...

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Abstract

The invention discloses a process of preparing of an over-expenditure structure chitose or an over-expenditure ethylene alcohol chitose, which comprises the following steps: degrading the chitose or the ethylene alcohol chitose with nitrous acid or nitrite; getting fractionally more narrow molecular weight distribution high molecular chain a end-groupof which is aldehyde group chitose or ethylene alcohol chitose with method of precipitation or volumetric exclusive chromatography; getting the Schiff's base dissolving in the weakly-acidic or neutral solution; getting the over-expenditure structure chitose or the over-expenditure ethylene alcohol chitose by deacidizing SCHIFF'S base( when R is H in the structural formula, the structure is the over-expenditure structure chitose; when R is CH2CH2OH, the structure is the over-expenditure ethylene alcohol chitose; wherein RI is the same structure branched chain to the broken line part in the above structural formula; the molecular weight range of the over-expenditure structure chitose or the over-expenditure ethylene alcohol chitose is >= 5000Da).

Description

technical field [0001] The invention belongs to the field of preparing chitosan, in particular to hyperbrached chitosan or hyperbrached glycol chitosan and a preparation method thereof. Background technique [0002] Since 1990, interest in chitin and chitosan has increased due to their superior biochemical properties. These properties are mainly manifested in: biodegradable properties, immune activity, antiviral activity and wound repair. In recent years, this kind of glycan compounds has achieved certain results in the fields of controlled drug release, cell culture and tissue engineering. Chitosan and its derivatives have been widely used in the field of pharmaceutical research due to their good physical and chemical properties and medicinal functions. In addition, chitosan, as a natural cationic polymer, forms a chitosan-DNA complex by electrostatically interacting with DNA, which can make DNA not easily degraded in vivo, and has low cytotoxicity, good biocompatibility,...

Claims

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Application Information

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IPC IPC(8): C08B37/08
Inventor 屈小中杨振忠
Owner INST OF CHEM CHINESE ACAD OF SCI
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