• Sebban, Muriel
• Oulyadi, Hassan
• Golten, Samuel
• Linclau, Bruno
• Light, Me

Abstract

The first single-crystal X-ray diffraction study of tetrafluorinated monosaccharide derivatives is presented.<br/>Both a- and b-methyl 2,3-dideoxy-2,2,3,3-tetrafluoro-D-galactopyranoside anomers adopt the<br/>4C1 conformation. The values for the C1–O1 and C1–O5 bond lengths and the O5–C1–O1–CH3 dihedral<br/>angles are in line with what can be expected from the anomeric and exo-anomeric effects. The chair conformations<br/>are slightly distorted, presumably due to repulsion between 1,3-diaxial C–O and C–F bonds.<br/>The asymmetric unit of both compounds contains up to three independent molecules, which differ in<br/>the conformation of the hydroxymethyl group (including in one case a ‘forbidden’ gg rotamer). The<br/>molecular packing of the b-anomer shows a clear segregation between fluorinated and hydrophilic<br/>domains, while for the a-anomer the regions of fluorine segregation are broken by interleafing of OMe<br/>groups. There is one close OH? ? ?F contact, which is likely to arise from the crystal packing. NMR studies<br/>show that the two anomers also adopt a 4C1 conformation in solution (D2O, CDCl3).

Topics

• impedance spectroscopy
• compound
• x-ray diffraction
• Nuclear Magnetic Resonance spectroscopy