Fu Y, He YX, Hou HX, Zhu WB, Li HL, Wu C, Xian FY. 2,2'-Anhydro-1-(3',5'-di-O-acetyl-β-D-arabinofuranosyl)uracil, a cyclouridine nucleoside with a C4'-endo furanosyl conformation.
Acta Crystallogr C 2013;
69:282-4. [PMID:
23459356 DOI:
10.1107/s0108270113000395]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 01/04/2013] [Indexed: 11/10/2022] Open
Abstract
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 ((4)E) 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.
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