Starch derivatives of high degree of functionalization. Part 2. Determination of the functionalization pattern of p-toluenesulfonyl starch by peracylation and NMR spectroscopy

Dicke, René; Rahn, Kerstin; Haack, Vera; Heinze, Thomas

doi:10.1016/s0144-8617(00)00219-8

Cited by 25 publications

(11 citation statements)

References 20 publications

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“…When starch (70% amylose) was tosylated in solution in DMA/LiCl, O-2 reacted preferentially, with very good regioselectivity (over O-3 and O-6), to give a product with a DS ≈ 1, with the tosyl groups essentially exclusively at C-2. The regioselectivity was proved by 1 H and 13 C NMR spectroscopy (Scheme 3) [62]. This regioselectivity is counterintuitive, and apparently, it is also solvent-dependent: Horton had previously reported that when the tosylation of amylose was carried out in pyridine, the more expected product, 6- O -tosyl-amylose, was formed with DS ≈ 0.6 (Scheme 3) [63].…”

Section: Saccharide Oxygen As Nucleophilementioning

confidence: 99%

Chemical Modification of Polysaccharides

Cumpstey¹

2013

ISRN Organic Chemistry

213

117

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This review covers methods for modifying the structures of polysaccharides. The introduction of hydrophobic, acidic, basic, or other functionality into polysaccharide structures can alter the properties of materials based on these substances. The development of chemical methods to achieve this aim is an ongoing area of research that is expected to become more important as the emphasis on using renewable starting materials and sustainable processes increases in the future. The methods covered in this review include ester and ether formation using saccharide oxygen nucleophiles, including enzymatic reactions and aspects of regioselectivity; the introduction of heteroatomic nucleophiles into polysaccharide chains; the oxidation of polysaccharides, including oxidative glycol cleavage, chemical oxidation of primary alcohols to carboxylic acids, and enzymatic oxidation of primary alcohols to aldehydes; reactions of uronic-acid-based polysaccharides; nucleophilic reactions of the amines of chitosan; and the formation of unsaturated polysaccharide derivatives.

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Section: Saccharide Oxygen As Nucleophilementioning

confidence: 99%

Chemical Modification of Polysaccharides

Cumpstey¹

2013

ISRN Organic Chemistry

213

117

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“…However, a quantification of partial DS at the respective position was not possible. An established method to obtain well resolved NMR spectra for a more precise structure analysis is the peracetylation of the remaining hydroxyl groups . As illustrated by the 13 C NMR spectrum of peracetylated sample 2c (DS = 0.18, Fig.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and structure characterization of soluble starch ethyl carbonates

Hampe

Heinze

2015

Starch - Stärke

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Starch ethyl carbonates were synthesized applying novel paths including chlorocarbonic acid ethyl ester and ethyl 1H-imidazole-1-carboxylate as reagent. The influence of starch, reaction medium, and base on the degree of substitution (DS) was investigated. The conversion of starch with chlorocarbonic acid ethyl ester in N,N-dimethyl formamide (DMF)/LiCl leads to a preferred substitution of position 6 of the anhydroglucose unit (AGU), on one hand. On the other, the reaction of starch with 1H-imidazole-1-carboxylate in dimethyl sulfoxide (DMSO) or DMF/LiCl results in a preferred functionalization of position 2. The products obtained were well soluble in polar aprotic solvents and in water depending on starch and DS. Intermolecular cross-linking or intramolecular cyclic carbonate formation could not be observed. A detailed structure characterization was carried out by one-and two-dimensional NMR spectroscopy.

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“…In contrast, Aburto et al (1999c) found for the homogeneous esterification of starch with FACl in the derivatizing solvent formic acid an increase of reactivity with decreasing amylose content in the starch sample. It might be assumed that the amylose dissolved in DMA/LiCl forms a special supramolecular order by strong interactions, which can even lead to products with a regioselective functionalization at position 2 as shown in detail for the tosylation of starch dissolved in DMA/LiCl , Dicke et al 2001.…”

Section: Homogeneous Esterification Of Starch With Facl In Dma/liclmentioning

confidence: 99%

“…Recently, the solvent N,N-dimethyl acetamide (DMA)/LiCl, usually applied for homogeneous phase chemistry of cellulose, has proved to be an efficient solvent in chemical modification of starch as well , Dicke et al 2001). Moreover, a number of very efficient reagents for in situ activation of the carboxylic acids were applied for acylation of cellulose.…”

Section: Introductionmentioning

confidence: 99%

Starch Derivatives of High Degree of Functionalization 11: Studies on Alternative Acylation of Starch with Long-chain Fatty Acids Homogeneously in N,N-dimethyl acetamide/LiCl

Grote

Heinze

2005

Cellulose

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Starch materials of different amylose content were allowed to react with saturated and unsaturated fatty acids of varying chain length from C 14 to C 18 under homogeneous conditions applying the solvent N,N-dimethyl acetamide in combination with LiCl. As reagent the corresponding acid chlorides and, alternatively, carboxylic acids in situ activated with toluene-4-sulfonyl chloride and N,N¢-carbonyldiimidazole (CDI) were studied. Using fatty acid chlorides (FACl) and toluene-4-sulfonyl chloride-activated acids an almost complete substitution of the starch occurs. By in situ activation of the fatty acids with CDI, products with a degree of substitution up to 2 were obtained, which, in particular, represents a simple and very mild procedure.

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Starch derivatives of high degree of functionalization. Part 2. Determination of the functionalization pattern of p-toluenesulfonyl starch by peracylation and NMR spectroscopy

Cited by 25 publications

References 20 publications

Chemical Modification of Polysaccharides

Chemical Modification of Polysaccharides

Synthesis and structure characterization of soluble starch ethyl carbonates

Starch Derivatives of High Degree of Functionalization 11: Studies on Alternative Acylation of Starch with Long-chain Fatty Acids Homogeneously in N,N-dimethyl acetamide/LiCl

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