Proton NMR spectroscopy assignment of d-glucose residues in highly acetylated starch

Laignel, Benoît; Bliard, Christophe; Massiot, Georges; Nuzillard, Jean‐Marc

doi:10.1016/s0008-6215(96)00314-x

Cited by 55 publications

(28 citation statements)

References 14 publications

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“…Table 2). [19,20] The TDS-starch 2 c is almost completely functionalized with TDS groups at the 6-O position. A lack of silylation on the primary hydroxyl groups of the AGU would be induce a significant downfield shifting of the methylene protons to 4.45 ppm (H-6 a) and 4.27 ppm (H-6b) due to the corresponding peracetylation.…”

Section: Resultsmentioning

confidence: 99%

Preparative and1H NMR Investigation on Regioselective Silylation of Starch Dissolved in Dimethyl Sulfoxide

Einfeldt¹,

Petzold²,

Günther³

et al. 2001

Macromol. Biosci.

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Section: Resultsmentioning

confidence: 99%

Preparative and1H NMR Investigation on Regioselective Silylation of Starch Dissolved in Dimethyl Sulfoxide

Einfeldt¹,

Petzold²,

Günther³

et al. 2001

Macromol. Biosci.

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“…The spectra were recorded at 507C, as recommended by Laignel et al [9]. IR spectra were recorded on a Spectrum 2000 FT-IR Spectrometer (Perkin Elmer, Norwalk, CT, USA).…”

Section: Analytical Equipmentmentioning

confidence: 99%

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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“…DS of modified KGM products was determined by means of the published titration method, 18 with some modifications. Briefly, the dried sample of powered KGM acetate (0.10 g) was placed in a 100 mL Erlenmeyer flask with a stopper and 75% ethanol (10 mL) was added.…”

Section: Determination Of Degree Of Substitution (Ds)mentioning

confidence: 99%

Lipase‐catalyzed acylation of konjac glucomannan in ionic liquids

Chen¹,

Zong²,

Li³

2006

J of Chemical Tech & Biotech

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A comparative study was made of lipase-catalyzed acylation of konjac glucomannan (KGM) with vinyl acetate as the acyl donor in five ionic liquids (ILs) and also in the presence of the organic solvent tert-butanol (t-BuOH). An obvious enhancement in enzyme activity and stability was observed using ILs as the reaction media when compared with t-BuOH. The maximum degree of substitution (DS) of the modified KGM in ILs and t-BuOH under the conditions employed is 0.71 and 0.54, respectively. The water activity (a w ) of the reaction system affected the acylation of KGM to some extent. 1-Butyl-3-methylimidazolium tetrafluoroborate (C 4 MIm.BF 4 ) was the best IL medium for the reaction, and an a w of 0.75 was optimum. It was also found that the nature of both the cation and the anion of ILs had an effect on the reaction. Candida antarctica lipase B immobilized on an acrylic resin (Novozym 435) displayed no acylation activity to KGM in 1-butyl-3-methylimidazolium chloride (C 4 MIm.Cl). The optimum reaction temperature for enzymatic acylation in ILs was shown to be 45-55• C. Enzymatic acylation of KGM in IL-t-BuOH co-solvent systems was also investigated. When an appropriate amount of t-BuOH was added to ILs, the DS of the modified KGM was enhanced. Additionally, the enzymatic acylation of KGM in all the media examined was shown to be regioselective, with acylation occurring predominantly at the C-6-OH.

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Proton NMR spectroscopy assignment of d-glucose residues in highly acetylated starch

Cited by 55 publications

References 14 publications

Preparative and1H NMR Investigation on Regioselective Silylation of Starch Dissolved in Dimethyl Sulfoxide

Preparative and1H NMR Investigation on Regioselective Silylation of Starch Dissolved in Dimethyl Sulfoxide

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

Lipase‐catalyzed acylation of konjac glucomannan in ionic liquids

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