The synthesis and the structural characterization by X-ray diffraction analysis of a monofunctionalized beta-cyclodextrin (beta-CD), the 6-deoxy-6-{4-[N-tert-butoxycarbonyl-2-aminoethyl]-imidazolyl}cyclomaltoh eptaose, are reported, It crystallizes in the orthorhombic space group P2(1)2(1)2(1), with a = 17.250(9)Angstrom, b = 19.45(1)Angstrom, c = 23.24(1)Angstrom, d(calc) = 1.304 g/cm(3) and Z = 4. The structure was refined to final indices R1 = 0.083 and wR2 = 0.24 (based on F-o(2)) for the 4843 observed reflection with I greater than or equal to 2 sigma(I). At the end of the refinement the presence of 12 water molecules per beta-CD molecule distributed over 16 sites was detected, In the solid state the monofunctionalized beta-CD molecule shows a 'sleeping swan'-like shape with the covalently bonded Boc-amino-ethyl-imidazolyl moiety forming a folded structure with its terminal part inserted inside the hydrophobic cavity of the beta-CD ring. The beta-CD macrocycle presents only small differences with respect to the conformation observed in hydrated uncomplexed or methylated beta-CDs. The macrocycle structure maintains an approximate seven-fold symmetry. The substituted beta-CD molecules pack in layers parallel to the be plane, The layers are stacked in an head-to-tail arrangement of the monomeric units, with formation of columns of molecules along the a axis, The layers are connected to each other by H-bonds through water molecules, Channels generated in the crystal by the packing of the macrocycles are filled with water molecules.

Functionalized cyclodextrins: Synthesis and structural characterization of 6-deoxy-6-{4-[N-tert-butoxycarbonyl-2-aminoethyl]-imidazolyl}-cyclomaltoheptaose

RIZZARELLI, Enrico;VECCHIO, Graziella
1996-01-01

Abstract

The synthesis and the structural characterization by X-ray diffraction analysis of a monofunctionalized beta-cyclodextrin (beta-CD), the 6-deoxy-6-{4-[N-tert-butoxycarbonyl-2-aminoethyl]-imidazolyl}cyclomaltoh eptaose, are reported, It crystallizes in the orthorhombic space group P2(1)2(1)2(1), with a = 17.250(9)Angstrom, b = 19.45(1)Angstrom, c = 23.24(1)Angstrom, d(calc) = 1.304 g/cm(3) and Z = 4. The structure was refined to final indices R1 = 0.083 and wR2 = 0.24 (based on F-o(2)) for the 4843 observed reflection with I greater than or equal to 2 sigma(I). At the end of the refinement the presence of 12 water molecules per beta-CD molecule distributed over 16 sites was detected, In the solid state the monofunctionalized beta-CD molecule shows a 'sleeping swan'-like shape with the covalently bonded Boc-amino-ethyl-imidazolyl moiety forming a folded structure with its terminal part inserted inside the hydrophobic cavity of the beta-CD ring. The beta-CD macrocycle presents only small differences with respect to the conformation observed in hydrated uncomplexed or methylated beta-CDs. The macrocycle structure maintains an approximate seven-fold symmetry. The substituted beta-CD molecules pack in layers parallel to the be plane, The layers are stacked in an head-to-tail arrangement of the monomeric units, with formation of columns of molecules along the a axis, The layers are connected to each other by H-bonds through water molecules, Channels generated in the crystal by the packing of the macrocycles are filled with water molecules.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/22551
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