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Molecular Modeling of Saccharides, Part IX.
On the Hydrophobic Characteristics of Cyclodextrins: Computer-Aided Visualization of Molecular Lipophilicity Patterns.
F. W. Lichtenthaler and S. Immel, Liebigs Ann. Chem. 1996, 27-37.
Abstract
Molecular Modeling of Saccharides, Part VI.
Small Ring Cyclodextrins: their Geometries and Hydrophobic Topographies.
S. Immel, J. Brickmann, and F. W. Lichtenthaler, Liebigs Ann. Chem. 1995, 929-942.
Abstract
Molecular Modeling of Saccharides, Part IV.
Cyclodextrins, Cyclomannins, and Cyclogalactins with five and six (1→4)-linked Sugar Units: a Comparative Assessment of their Conformations and Hydrophobicity Potential Profiles.
F. W. Lichtenthaler and S. Immel, Tetrahedron: Asymmetry 1994, 5, 2045-2060.
Abstract
A detailed PIMM91 force-field[1] based evaluation of the molecular geometries of small-ring cyclodextrins with three, four, and five α(1→4)-linked glucose residues, and the starch-derived α-cyclodextrin was performed by using molecular mechanics and high-temperature annealing. The resulting minimum-energy structures reveal that the progressive strain imposed by diminution of the cyclodextrin macrocycle from six to three units is reflected in a widening of the intersaccharidic torsion angle, in a complex balance of the interrelated glucose tilt angles and the glycosidic torsions. Most strikingly, a specific unilateral distortion of the pyranoid rings, i.e. flattening at C-4 towards the E1 envelope conformation,is observed in the small ring cyclodextrins.
The larger, naturally occurring cyclodextrins with six and more glucose units become more flexible with increasing ring size. Due to the presence of a central cavity with hydrophobic character, these molecules are able to form inclusion complexes with a large variety of small organic compounds such as substituted benzenes.
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