Conformational flexibility in a triazole nucleoside derivative: 4-cyano-5-cyanomethyl-1-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)-1,2,3-triazole.

The crystal-structure determination of the molecular structure of the hydrophobic compound, 4-cyano-5-cyanomethyl-1-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)-1,2,3-triazole, C16H17N5O7, provides us with two different conformations of ribofuranosyl moieties [(C2'-exo, C3'-endo) and C2'-exo] with two markedly different N-glycosidic angles. There are two molecules in the asymmetric unit of the crystal and the overall stereochemistry of the molecules are influenced predominantly by weak intramolecular bifurcated and trifurcated hydrogen bonds of the type C-H...O and C-H...N, where endo-H atoms attached to C2' and C3' are involved. The molecules in the crystal are interconnected with longer intermolecular bonds of the same type. There are empty channels (occupying 14.0% of the whole volume of the unit cell), which are extended along b-axis of the entire crystal.

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