Saccharides, addition

With increasing availability of 13C-enriched saccharides, additional 13C- H and 13C-13C coupling constants have provided valuable information to confirm and/or extend structural conclusions based on the traditional proton-based NMR data. 

Figure 12.6 Effect of saccharide addition on morphology of submicrospheres.

It is known that the acidity of monoboronic acids is intensified when they form covalent complexes with diols[3-7,l 1-13]. Hence, at constant pH the saccharide addition can change neutral boronic acids to anionic boronate esters. In fluorescent monoboronic acids this change is reflected as a decrease in the fluorescence intensity (/) of the neighboring fluorophore[l 1-13]. Typical examples are compounds 1-5. 

Analysis and Specifications. Typical product analyses include sohds level, ash, color, conductivity, purity, and minor saccharide levels (19). Specifications for anhydrous and monohydrate crystalline dextrose are available (15). High quahty anhydrous dextrose produced for the pharmaceutical industry is prepared in accordance with additional specifications (20). 

Boronic acid-containing polyaniline has also been utilized in diabetes-related research. One such polymer (23) (Fig. 17) has been observed to exhibit a linear near-infrared optical response to saccharides.43 The polymer was prepared by the copolymerization of aniline with 3-aminophenylboronic acid using lOmM (NH4)S208 in 1M HC1. The films were observed to undergo changes in the absorption spectra on addition of saccharides at pH 7.2. 

The high space-time yields are the result of a doubling time of only 30 min and its applicability for high cell-density cultures. However, it is hardly possible to excrete overexpressed proteins into cultivation media. In addition, accumulation of pyrogenic lipopoly-saccharides in its outer membrane (a distinctive feature of Gram-negative bacteria) make additional purification steps necessary if pharmaceutical proteins are produced by E. coli [29]. 

With the introduction of new building technologies, namely application of synthetic polymeric additives, the natural organic additives gradually disappeared [24]. At present, builders are returning to them in particular, biomolecules (saccharides and their derivatives, oils, waxes, etc.) produced by biotechnological procedures have been reintroduced [25]. 

Heterogeneous catalysts, particularly zeolites, have been found suitable for performing transformations of biomass carbohydrates for the production of fine and specialty chemicals.123 From these catalytic routes, the hydrolysis of abundant biomass saccharides, such as cellulose or sucrose, is of particular interest. The latter disaccharide constitutes one of the main renewable raw materials employed for the production of biobased products, notably food additives and pharmaceuticals.124 Hydrolysis of sucrose leads to a 1 1 mixture of glucose and fructose, termed invert sugar and, depending on the reaction conditions, the subsequent formation of 5-hydroxymethylfurfural (HMF) as a by-product resulting from dehydration of fructose. HMF is a versatile intermediate used in industry, and can be derivatized to yield a number of polymerizable furanoid monomers. In particular, HMF has been used in the manufacture of special phenolic resins.125... 

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