Fu Ying, He Yin-Xia, Hou Hong-Xia, Zhu Wen-Bo, Li Hu-Lin, Wu Chao, Xian Fang-Yan
Key Laboratory of Polymer Materials of Gansu Province, The Key Laboratory of Ecological Environment Related Polymer Materials of the Ministry of Education, Incorporated in the Local and Provincial College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, People's Republic of China.
Acta Crystallogr C. 2013 Mar;69(Pt 3):282-4. doi: 10.1107/S0108270113000395. Epub 2013 Feb 12.
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.
2,2'-脱水-1-(3',5'-二-O-乙酰基-β-D-阿拉伯呋喃糖基)尿嘧啶（C₁₃H₁₄N₂O₇）是通过在乙酸酐中回流2',3'-O-(甲氧基亚甲基)尿苷得到的。该结构呈现出近乎完美的C4'-内型((4)E)构象。五元呋喃糖环的最佳四原子平面是O-C-C-C，涉及稠合五元恶唑烷环的C原子，扭转角仅为-0.4 (2)°。恶唑烷环与六元尿嘧啶环基本共面[r.m.s.偏差 = 0.012 (5) Å，二面角 = -3.2 (3)°]。环外C-C键处的构象是反式- gauche构象，通过各种C-H...π和C-O...π相互作用得以稳定。
