Conformational Flexibility in a Triazole Nucleoside Derivative: 4‐Cyano‐5‐cyanomethyl‐1‐(2,3,5‐tri‐O‐acetyl‐β‐d‐ribofuranosyl)‐1,2,3‐triazole

Abstract

The crystal‐structure determination of the molecular structure of the hydrophobic compound, 4‐cyano‐5‐cyanomethyl‐1‐(2,3,5‐tri‐O‐acetyl‐β‐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.

^†In honor and celebration of the 70th birthday of Professor Leroy B. Townsend.

Keywords:

• β‐d‐ribofuranosyl nucleoside
• Glycosidic bond
• Conformational analysis

Acknowledgments

The financial support of the Ministry for Education, Science and Sport, Republic of Slovenia, Slovenia through regular research grants Nos. P0‐511‐2003 and P0‐515‐2003 is gratefully acknowledged.

Notes

^†In honor and celebration of the 70th birthday of Professor Leroy B. Townsend.