Starch thiols

Starch thiols can have the SH group directly on the pyranose ring or in a side chain. There are several methods of synthesizing starch thiols of the first type. One of them is based on the pyrolysis of starch xanthates (32), but the reaction proceeds in two parallel routes one producing thionates (35) and the other producing thiols (37).2675,2677 Reduction of starch xanthates with NaBPU in alkali is another approach to thiols. Thiols prepared in this manner were subjected to graft polymerization with vinyl polymers. Nucleophilic substitution of the chlorine... 

The latter method has the advantage of recycling the natural or waste product. Significant examples are cotton modified with amines [3, 4], starch utilized in xanthate form [5, 6, 7], thiol type keratine gel prepared from the wool [8, 9,10], wool simply reduced [11] or modified with amine groups [12, 13, 14] and finally polysaccharides such as cellulose [15, 16, 17], glucose [18] or polyosides [19] modified with thiol or amine groups. 

Many interactions are of a pure chemical nature and may result from the presence of aldehydes and their reactivity toward amino and thiol groups of proteins. Another frequently occurring type of interaction is the formation of hydrogen bonds between food compounds and polar flavor components such as alcohols. Starch, starch-derived maltodextrins, and (3-cyclodextrin are able to form inclusion complexes with many flavor components. Many other interactions, although of great influence on flavor perception, are of a physical nature and therefore not mentioned in this chapter. 

Starch dialdehyde reacts with thiols to form dithioacetals.525 Thiol groups in thiol acids undergo oxidation in air into disulfides.2681... 

Some natural polymers have also been used as support for Schiff base ligands. A starch support has also been used as support for a PyBox. A telomerized starch 96 [91] presenting a final double bound reacted with a thiol-PyBox in the presence of AIBN (Scheme 45) to form the corresponding immobilized PyBox. [92] Although the Ru-97 complex exhibited lower activity (up to 44% after the third reuse) and selectivity (trans/cis 76/24 with 50% ee for the... 

Carbohydrate UV-visible spectroscopy is essentially that of any substituents that have spectroscopy a simple sugar system such as starch has no spectroscopy above 200 nm. Carbohydrates are typically deriva-tized with thiols or aromatic chromophores for UV spectroscopy. The spectroscopy of these compounds is largely determined by that of the derivatives. These data may be found in UV-visible spectroscopy atlases. 

Imaging/Labeling Applications Actin filaments amino acids amyloid Ap peptides bacteria cells glycopeptide hairs metal ions (copper ions, iron ions, chromium ions, lead ions, mercury(ll) ions, nitrite ions ) microorganisms monosaccharides nucleic acids proteins protoplasts sperms starch granules superoxide anions thiols ... 

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