SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF (II)-DIAMINO-6(I),6(II)-DIDEOXY-CYCLOMALTOHEPTAOSE A DIFUNCTIONALIZED BETA-CYCLODEXTRIN

(II)-Diamino-6(I),6(II)-dideoxy-cyclomaltoheptaose was prepared using the regioselective procedure described by Tabushi. The difunctionalize d beta-cyclodextrin crystallizes as hextadecahydrate in the orthorhomb ic space group P2(1)2(1)2(1), with a = 11.395(3), b = 32.989(9), c = 1 7.560(5) Angstrom, V = 6601 Angstrom(3), Z = 4, The structure was solv ed by molecular replacement techniques using the program PATSEE and wa s refined to a conventional final R = 0.058 for the 5031 observed refl ections with 1 greater than or equal to 3 sigma(I). The beta-CD macroc ycle presents only slight differences with respect to uncomplexed hydr ated or methylated beta-CD. The macrocycle structure maintains an appr oximate seven-fold symmetry. The round shape of the cyclodextrin ring is stabilized by intramolecular O-H ... O H-bonds between the secondar y 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 c losed at each end by neighbouring molecules. The macrocycles are direc tly linked to each other by H-bonds involving either primary and secon dary hydroxyl or amino groups of symmetry-related molecules. The resul ting layers are connected to each other by a dense intermolecular hydr ogen-bond network, in which solvent molecules participate.