Cyclodextrins guests

Hursthouse, M. B., Smith, C. Z., Thornton-Pett, M., and Utley, J. H. P. 1982. The x-ray crystal structure of an ethyl cinnamate-fS-cyclodextrin guest-host compLfoChem. Soc. Chem. Commun., 15 881-882. 

Many plant secondary metabolites produced by cell cultures and substrates used in culture media are often hydrophobic and have low solubility in aqueous medium. Improving the production of metabolites in the plant cell system has also been attempted by enhancing the solubilities of metabolites by using the cyclodextrin-guest complex formation. There are two major approaches, one involves the improvement of substrate solubility and the other improves metabolite. 

Table 9.2 Molar fractions of the (3-cyclodextrin-guest complexes [f(j-G)]a determined by ESI-MS on-chip experiments and data based on microcalorimetric studies.

Harada A, Takashima Y, Nakahata M (2014) Supramolecular polymeric materials via cyclodextrin-guest interactions. Acc Chem Res 47 2128-2140... 

To overcome the solubility constraints, a water-soluble complex with P-CD and Azadirachtin has been reported. The binding constants measured by NMR titration for Azadirachtin with a-, P-, and y-CDs are, ca. 0, 238 and 73 M, respectively. The mutual affinity of Azadirachtin and P-CD shows that both size and shape play a critical role. The NMR studies also revealed the presence of both 1 1 and 2 1 cyclodextrin-guest complexes in solution. 

Cyclodextrins have had valuable industrial uses for a considerable time, particularly as agents to bind or release volatile molecules. Accurate predictions concerning the selectivity and stability of cyclodextrin-guest complexes are therefore of considerable interest both academically and practically." MD was used to simulate cyclodextrin hydrates" as a test of the applicability of the GROMOS program package to systems beyond proteins and nucleic acids. Other early MD simulations focused on interactions with guests such as enantiomers of methyl-2-chloropropionate. Comparisons between calculated thermodynamic properties for complexes formed by O -cyclodextrin with para-substituted phenols and the results of MM simulations led to improvements in force fields that described the interactions. MM2 simulations were used to support NMR data for the -cyclodextrin inclusion complex with benzoic acid. " The well-known catalytic effect of cyclodextrins has been modeled. For example, the relative rate increase of hydrolysis of S over R phenyl ester stereoisomers in the presence of -cyclodextrin... 

The concept of cyclodextrin guest inclusion has been extended to the synthesis of a library of multicavity dimers and trimers of cyclodextrin that can bind specific guest molecules to mimic enzymes (Figure 6) Such supramolecular structures were tested with mono-, di-, and tri-substituted Gd + complexes bearing hydrophobic cyclohexyl moieties for interaction with the cyclodextrin cavities. The relaxivity enhancement increased with the number of cyclohexyl groups on the Gd + chelate. Further, the cyclodextrin trimer host-guest supramolecule with the tri-substituted Gd " " complex exhibited the greatest relaxivity... 

I. C. Paul What happens when you heat the crystals of the cyclodextrin guest complexes How stable are the crystals to heat Do they retain the guest molecules at higher temperatures ... 

Since calixarenes can be functionalized almost at will at their upper or lower rim, they represent good candidates for new stationary phases. Similar to cyclodextrins, guests can in principle be inserted into the hydrophobic interior of the cone-shaped macrocycles. To this end, calixarenes of different ring sizes have been immobilized on silica gel and were studied with respect to their discrimination between nucleosides and nucleobases in HPLC separations. 

Tabular Listing of Calculated Cyclodextrin-Guest Inclusion Complexes 6.1 MOLECULAR MECHANICS CALCULATIONS... 

Busch KW, Busch MA (2006) Chiral analysis by regression modeling of spectral data in chiral analysis. In Kenneth WB, Marianna AB (eds) Elsevier, Amsterdam, pp 363-396 Busch KW, Swamidoss IM, Fakayode SO et al (2003) Determination of the enantiomeric composition of guest molecules by chemometric analysis of the UV-visible spectra of cyclodextrin guest-host complexes. J Am Chem Soc 125 1690-1691 Busch KW, Swamidoss IM, Fakayode SO et al (2004) Determination of the enantiomeric composition of some molecules of pharmaceutical interest by chemometric analysis of the UV spectra of cyclodextrin guest-host complexes. Anal Chim Acta 525 53-62 Fakayode SO, Swamidoss IM, Busch MA et al (2005) Determination of the enantiomeric composition of some molecules of pharmaceutical interest by chemometric analysis of the UV spectra of guest-host complexes formed with modified cyclodextrins. Talanta 65 838-845... 

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