2,2′-Anhydro-1-(3′,5′-di-O-acetyl-β-D-arabinofuranosyl)uracil, a cyclouridine nucleoside with a C4′-endo furanosyl conformation
International Union of Crystallography, 2013
Acta Crystallographica Section C
Volume 69, Issue 3, pages 282–284, March 2013
How to Cite
Fu, Y., He, Y.-X., Hou, H.-X., Zhu, W.-B., Li, H.-L., Wu, C. and Xian, F.-Y. (2013), 2,2′-Anhydro-1-(3′,5′-di-O-acetyl-β-D-arabinofuranosyl)uracil, a cyclouridine nucleoside with a C4′-endo furanosyl conformation. Acta Crystallographica C, 69: 282–284. doi: 10.1107/S0108270113000395
2,2′-Anhydro-1-(3′,5′-di-O-acetyl-β-D-arabinofuranosyl)uracil, C13H14N2O7, was obtained by refluxing 2′,3′-O-(methoxymethylene)uridine in acetic anhydride. The structure exhibits a nearly perfect C4′-endo (4E) conformation. The best four-atom plane of the five-membered furanose ring is O—C—C—C, involving the C atoms of the fused five-membered oxazolidine ring, and the torsion angle is only −0.4 (2)°. The oxazolidine ring is essentially coplanar with the six-membered uracil ring [r.m.s. deviation = 0.012 (5) Å and dihedral angle = −3.2 (3)°]. The conformation at the exocyclic C—C bond is gauche–trans which is stabilized by various C—H...π and C—O...π interactions.