Synthesis and structural characterization of 6I,6II-diamino-6I,6II-dideoxy-cyclomaltoheptaose, a difunctionalized beta-cyclodextrin.
6I,6II-Diamino-6I,6II-dideoxy-cyclomaltoheptaose was prepared using the regioselective procedure described by Tabushi. The difunctionalized beta-cyclodextrin crystallizes as hexadecahydrate in the orthorhombic space group P2(1)2(1)2(1), with a = 11.395(3), b = 32.989(9), c = 17.560(5) A, V = 6601 A3, Z = 4. The structure was solved by molecular replacement techniques using the program PATSEE and was refined to a conventional final R = 0.058 for the 5031 observed reflections with I > or = 3 sigma(I). The beta-CD macrocycle presents only slight differences with respect to uncomplexed hydrated or methylated beta-CD. The macrocycle structure maintains an approximate seven-fold symmetry. The round shape of the cyclodextrin ring is stabilized by intramolecular O-H ... O H-bonds between the secondary hydroxyl groups of neighbouring glucose residues. Along the a axis, the beta-CD molecules are arranged in columns; the macrocycles form a herring-bone pattern, so that the cavity of each beta-CD molecule is closed at each end by neighbouring molecules. The macrocycles are directly linked to each other by H-bonds involving either primary and secondary hydroxyl or amino groups of symmetry-related molecules. The resulting layers are connected to each other by a dense intermolecular hydrogen-bond network, in which solvent molecules participate.
Di Blasio
B
B
Dipartimento di Chimica, Università della Basilicata, Potenza, Italy.
Galdiero
S
S
Saviano
M
M
Pedone
C
C
Benedetti
E
E
Rizzarelli
E
E
Pedotti
S
S
Vecchio
G
G
Gibbons
W A
WA
D002240:Carbohydrate Sequence; D003505:Cyclodextrins / Q000138:chemical synthesis* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009904:Optical Rotation; D016339:Spectrometry, Mass, Fast Atom Bombardment; D014961:X-Ray Diffraction; D047392:beta-Cyclodextrins
C099042:6(I),6(II)-diamino-6(I),6(II)-dideoxycyclomaltoheptaose; D003505:Cyclodextrins; D047392:beta-Cyclodextrins; C031215:betadex