Cyclo dextrin chemistry

Another common theme that authors use to establish importance involves environmental impacts. For example, an environmental slant is used in the first sentence of the cyclodextrin article (P3, exercise 6.7), where the study of cyclo-dextrins is justified based on their role in soil remediation. The importance of work that benefits air or water quality and/or promotes green chemistry can also be stressed. Work is also viewed as important if it has cross-disciplinary applications. For example, in the Introduction section of the tetrazole article, the authors stress the importance of tetrazoles in coordination chemistry, medicinal chemistry, and in various materials science applications and point out their role as useful intermediates in the preparation of substituted tetrazoles ... 

Biomimetic Chemistry, including that involved in the synthesis and study of artificial enzymes, has grown to enormous proportions. Even the part of the field using cyclo-dextrins as binding groups in synthetic catalysts that mimic enzymes has been the subject of a large review article [1]. Thus in this chapter I will focus mainly, but not exclusively, on work from our own laboratory. Other chapters will help make up for this somewhat narrow focus. I have published several reviews of our work elsewhere [2-51]. 

The choice of polymer is determined by considering the solubility of the metal colloid precursor, the solvent of choice, and the ability of the polymer to stabilize the reduced metal particles in the colloidal state. Natural polymers such as gelatin and agar were often used before the advent of synthetic polymer chemistry, and related stabilizers such as cellulose acetate, cellulose nitrate [23] and cyclo-dextrins [24] have been used more recently. Thiele [25] proposed the Protective Value as a measure of the ability of a polymer to stabilize colloidal metal. It was defined, similar to the older Gold Number of Zsigmondy, as the weight of the... 

As already cited, bifunctionalized or multifunctionalized cyclo-dextrins have versatile applications to biomimetic chemistry as it is seen in a retinal pigment model(9). 

On treatment with potassium iodide, the capped disulfonate j8-cyclo-dextrin discussed above could easily be converted to the corresponding diiodide jS-cyclodextrin. With appropriate nucleophiles (imidazole, histamine) a new route to bis(iV-imidazolyl)-j8-cyclodextrin and bis(iV-histamino)-j8-cyclodextrin was developed by Tabushi s team (182). In the presence of Zn(II) ion, both regiospecifically bifunctionalized cyclodextrins hydrate CO2 and are the first successful carbonic anhydrase models. The Zn(II) ion binds to the imidazole rings located in the edge of the cyclodextrin pocket and the presence of an additional basic group, as with bis(histamino)-cyclodextrin-Zn(II), enhances the activity. Therefore, the present models show that all three factors, Zn(II)-imidazole, hydrophobic environment, and a base seem to help to generate the carbonic anhydrase activity (182). The chemistry of this enzyme is further discussed in Section 6.2, p. 331. 

Recently, click chemistry has emerged as a versatile and viable platform for the development of hydrogels due to its high reactivity, bioorthogonality, high specificity, and high yield. Various hydrogels based on PVA (Ossipov and Hilbom 2006), PEG (van Dijk et al. 2010), PNIPAM/HEMA (Xu et al. 2008), PNIPAM/j -cyclo-dextrin ( -CD) (Xu et al. 2009), HA (Crescenzi et al. 2007), etc. were fabricated... 

J. Szejtli, Inclusion of Guest Molecules, Selectivity and Molecular Recognition by Cyclo-dextrins, in J. Szejtli, T. Osa (Eds), Cyclodextrins Comprehensive Supramolecular Chemistry, Vol. 3, Elsevier Science, Amsterdam, 1996, p. 189. 

The application of these studies to the chemistry and pharmaceutic of cyclo-dextrins open the way to design of novel drug delivery sytems for specific cellular targeting (i.e. targeted PDT) [69]. 

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