Functionalized cyclodextrins: Synthesis and structural characterization of 6-deoxy-6-{4-[N-tert-butoxycarbonyl-2-aminoethyl]-imidazolyl}-cyclomaltoheptaose
Functionalized cyclodextrins: Synthesis and structural characterization of 6-deoxy-6-{4-[N-tert-butoxycarbonyl-2-aminoethyl]-imidazolyl}-cyclomaltoheptaose(457 views) Di Blasio B, Galdiero S, Saviano M, De Simone G, Benedetti E, Pedone C, Gibbons WA, Deschenaux R, Rizzarelli E, Vecchio G
Keywords: β-Cyclodextrins, Conformation, Monofunctionalized Cyclodextrins, Solid State Structure, Synthesis,
Affiliations: Dipartimento di Chimica, Università della Basilicata, Via N. Sauro 85, 85100 Polenza, Italy
Biocrystallography Research Centre, C.N.R., Univ. Federico II di Napoli, via Mezzocannone, 4, 80134 Napoli, Italy
Department Pharmaceutical Chemistry, University of London, Brunswick Square 29, WC IN 1AX London, United Kingdom
Institut de Chimie, Université de Neuchâtel, Av. de Bellevaux 51, 2000 Neuchâtel, Switzerland
Dipartimento di Scienze Chimiche, Università di Catania, V.le A. Doria 8, 95125, Catania, Italy
Ist. Stud. delle Sostanze N., V.le A. Doria 8, 95125 Catania, Italy
References: Not available.
Functionalized cyclodextrins: Synthesis and structural characterization of 6-deoxy-6-{4-[N-tert-butoxycarbonyl-2-aminoethyl]-imidazolyl}-cyclomaltoheptaose
The synthesis and the structural characterization by X-ray diffraction analysis of a monofunctionalized β-cyclodextrin (β-CD), the 6-deoxy-6-{4-[N-tert-butoxycarbonyl-2-aminoethyl]-imidazolyl}- cyclomaltoheptaose, are reported. It crystallizes in the orthorhombic space group P212121, with a = 17.250(9)Å, b = 19.45(1)Å, c = 23.24(1)Å, dcalc = 1304 g/cm3 and Z = 4. The structure was refined to final indices R1 = 0.083 and wR2 = 0.24 (based on Fo 2) for the 4843 observed reflection with I ≥ 2σ(I). At the end of the refinement the presence of 12 water molecules per β-CD molecule distributed over 16 sites was detected. In the solid state the monofunctionalized β-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 β-CD ring. The β-CD macrocycle presents only small differences with respect to the conformation observed in hydrated uncomplexed or methylated β-CDs. The macrocycle structure maintains an approximate seven-fold symmetry. The substituted β-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
Functionalized cyclodextrins: Synthesis and structural characterization of 6-deoxy-6-{4-[N-tert-butoxycarbonyl-2-aminoethyl]-imidazolyl}-cyclomaltoheptaose