Cyclodextrins gamma-cyclodextrin

Inclusion compounds of the Cg aromatic compounds with tris((9-phenylenedioxy)cyclotriphosphazene have been used to separate the individual isomers (43—47). The Schardinger dextrins, such as alpha-cyclodextrin, beta-dextrin, and gamma-dextrin are used for clathration alpha-dextrin is particularly useful for recovering PX from a Cg aromatic mixture (48,49). PyromeUitic dianhydride (50) and beryllium oxybenzoate (51) also form complexes, and procedures for separations were developed. 

A derivatization with acid chlorides is also possible. Amino acids can be derivatized with 9-fluorenylmethyl chloroformate (FMOC) and separated on a CSP with X-cyclodextrin (ChiraDex gamma ), a cyclic oligosaccharide which consists of eight glucose units. 

G. Chambers, C. Carroll, G.F. Farrell, A.B. Dalton, M. McNamara, M.I.H. Panhuis, and H.J. Byrne, Characterization of the interaction of gamma cyclodextrin with single-walled carbon nanotubes. Nano... 

Andersson T, Nilsson K, Sundahl M, Westman G, Wennerstroem O (1992) Cm embedded in gamma-cyclodextrin a water-soluble fullerene. Chem. Commun. 604-606. 

Braun T, Buvari-Barcza A, Barcza L, Konkoly-Thege I, Fodor M, Migali B (1994) Mechanochemistry a novel approach to the synthesis of fullerene compounds. Water soluble Buckminster fullerene - gamma- cyclodextrin inclusion complexes via solid-solid reaction. Solid State Chem. 74 47-51. 

Arima, H., F. Kihara, F. Hirayama, and K. Uekama. 2001. Enhancement of gene expression by polyamidoamine dendrimer conjugates with alpha-, beta-, and gamma-cyclodextrins. Bioconjug Chem 12(4) 476-84. 

Koppenhoeffer, B., Epperlein, U., Jakob, A., Wuerthner, S., Xiaofeng, Z., Bingcheng, L. Separation of enantiomers of drugs by capillary electrophoresis, part 7. Gamma-cyclodextrin as chiral solvating agent. Chirality 1998, 10, 548-554. 

G1c -6 + alpha cyclodextrin G1c -7 + beta cyclodextrin G1c -8 + gamma cyclodextrin... 

Fig. 8.—Variation of 1/t Characterizing the Crystal Violet-Gamma Cyclodextrin System with Variation of Total Concentration of Gamma Cyclodextrin [[Crystal Violet] = 1.5 X 10 mol. dm" T = 25°C. Adapted from Fig. 3 of R. L. Schiller, J. H. Coates, and S. F. Lincoln, J. Chem. Soc. Faraday Trans. 1, 80 (1984) 1257-1266.]...

However, if the dye is of an appropriate size to form a one host-two guests complex with beta or gamma cyclodextrin, it was found that, on addition of the cyclodextrin, dye solutions often show spectral changes... 

Fig. 9.—Schematic Diagram of the Two Hosts-Two Guests Inclusion Mechanism Shown for the Tropaeolin 000 No. 2-Gamma Cyclodextrin System.

The same mechanism was also proposed by Herkstroeter and coworkers,who carried out absorption and fluorescence measurements on the interaction of 4-pyrenyl butanoate with gamma cyclodextrin. No kinetic studies, however, have yet been performed on these systems in order to verify the proposed mechanism. 

An interesting equilibrium study was performed by Kasatani and coworkers on the interaction of a series of cyanine dyes with beta and gamma cyclodextrin, using u.v.-visible spectrophotometric measurements. The results were consistent with the enhancement of dimer formation by inclusion of the dye molecules within the cyclodextrin. As expected from the work of others, such geometrical factors " as the size of the aromatic groups and the lengths of the central methine chains strongly influence the occurrence of dimer formation within the cyclodextrin cavity. 

Some other interesting modifications of the gamma cyclodextrin structure have been made by the group of Ueno and coworkers. By the... 

Fig. 10.—Schematic Diagram of the Space Regulation of the Gamma Cyclodextrin Cavity by an Appended Naphthalene Moiety.

Fig. 11.—Schematic Diagram of the Interaction of a Guest with Gamma Cyclodextrin Bearing Two Naphthyl Groups. [Ueno and coworkers proposed two possible mechanisms of inclusion, I and 2. In 1, one of the naphthyl groups acts as a space regulator. In 2, the two naphthyl groups form a flexible, hydrophobic cap across the cavity of the cyclodextrin. In the cases of the guests that they investigated, Ueno considered that mechanism 2 is predominant.]...

Preparation of cyclodextrin derivatives substitution at a secondary hydroxyl group of the cyclodextrin annulus. Murakami and cowor-kers described a new and convenient method for the regioselective tosylation of the 2-hydroxyl groups of alpha, beta, and gamma cyclodextrin by means of a cyclic tin intermediate. The method is based on the reaction of dibutyltin oxide with 1,2-diols to form five-membered dibutyl-stannylidene derivatives. Useful yields of the 2-6>-tosyl derivatives of the cyclodextrins were obtained. 

Cyclodextrin Action Pattern. The action pattern of alpha-, beta-, or gamma-cyclodextrin was determined by BioRad Aminex Carbohydrate HPX-42A HPLC with two columns in tandem at 85 C eluting with glass distilled water as at a flow rate of 0.6 ml/minute. Detection was by refractive index. 

Cyclodextrins, products of the degradation of starch by an amylase of Bacillus macerans(1), have been studied in terms of chemical modifications, mainly for the purpose of developing efficient enzyme mimics(2). Not only their unique cyclic structures, but also their ability to form Inclusion complexes with suitable organic molecules, led us to Investigate the total synthesis of this class of molecules(3) We describe here an approach to a total synthesis of alpha(l), gamma(2), and "iso-alpha" cyclodextrin (3). 

---