Based on mono- and disaccharides

DIRUKOV Monomers and Polymers Based on Mono-and Disaccharides 177... 

The synthesis of novel polymers, mostly polyesters and polyurethanes, based on mono and disaccharides (Hg. 1.15), together with their properties and possible applications, are described in Chapter 5. 

A new NMR method for the determination of the anomeric configuration in mono- and disaccharides has been described.18 The protocol is based on the different cross-correlated relaxation between proton chemical shift anisotropy (CSA) and dipolar relaxation for the a and (3 anomers of sugars. Only the ot-anomers show the presence of CSA (HI or Hl )-proton dipole (H1-H2 or Hl -H2 ) in the longitudinal relaxation of the anomeric protons. The method is of special interest for cases in which vicinal coupling constants between HI and H2 in both anomers a and (3 are similar and small, such as D-mannose, and the non-ambiguous description of the anomeric configuration needs additional measurements. 

Preparation of the chapter was based on a literature search through SCOPUS and the Beilstein Database, which identified 53 papers of value and which are discussed in this chapter. It is remarkable that so few papers appeared on fused thietanes and thietes during this period, and many of them are a continuation of previously published studies. To the best of our knowledge, only taxoids with fused thietane rings as well as mono- and disaccharides bearing fused thietane moieties constitute new classes of fused-ring thietanes and thietes. 

In the present experiment, we measure the amount of the active ingredient, acetylsalicylic acid (see also Experiment 35), in common aspirin pills. Companies use different fillers and in different amounts, but the active ingredient, acetylsalicylic acid, must be the same in every aspirin tablet. We separate the acetylsalicylic acid from the filler based on their different solubilities. Acetylsalicylic acid is very soluble in ethanol, while neither starch, nor other polysaccharides, or even mono- and disaccharides used as a fillers, are soluble in ethanol. Some companies may use inorganic salts as fillers but these too are not soluble in ethanol. On the other hand, some specially formulated aspirin tablets may contain small amounts of ethanol-soluble substances such as stearic acid or vegetable oil. Thus the ethanol extracts of aspirin tablets may contain small amounts of substances other than acetylsalicylic acid. 

Titanium-based catalysts, would seem particularly attractive candidates, but the pore size of e.g. TS-1, is much too small to admit even a monosaccharide. Recently a number of synthetic approaches towards mesoporous titanium containing catalysts of the MCM-41 type have appeared in the literature . In the present paper we will deseribe the use of Ti-MCM-41 materials in the oxidation of the model mono- and disaccharides methyl a-D-glucopyranoside, sucrose and a,a-trehalose, and we will discuss the effect of the zeolite synthesis on the effectiveness in these reactions. Several preparative approaches of Ti-MCM-41 have been compared in the oxidation of these model carbohydrates. 

This chapter gives a general introduction to the book and describes briefly the context for which the editors established its contents and explains why certain topics were excluded from it. It covers the main raw materials based on vegetable resources, namely (i) wood and its main components cellulose, lignin, hemicelluloses, tannins, rosins and terpenes, as well as species-speciflc constituents, like natural rubber and suberin and (ii) annual plants as sources of starch, vegetable oils, hemicelluloses, mono and disaccharides and algae. Then, the main animal biomass constituents are briefly described, with particular emphasis on chitin, chitosan, proteins and cellulose whiskers from molluscs. Finally, bacterial polymers such as poly(hydroxyalkanoates) and bacterial cellulose are evoked. For each relevant renewable source, this survey alerts the reader to the corresponding chapter in the book. 

The traditional use of some of the most important mono and disaccharides as sweeteners, whether energetic or not, is of course outside the scope of this book. The interest in using this family of compounds, produced by different annual plants, as precursors to novel materials, has increased considraably in recent years, mostly in three different directions, viz. (i) the conversion of fructose to hydroxymethyl furfural (Rg. 1.14), (ii) the synthesis of polycondensation materials using sugars as comonomers and (iii) the preparation of surfactants based on renewable resources. 

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