A series of analogues of anhydrouridine have been synthesized and their crystal structures established using X-ray diffraction. For all cases, the ribose ring has 0(4')-exo, C(4')-endo pucker and the pyrimidine base is in the anti conformation. Investigated compounds crystallize in different crystal systems (monoclinic, orthorhombic), have different space group symmetry (P2(1), P2(1)2(1)2(1)) and exhibit different intermolecular interactions (halogen and hydrogen bonds) among molecules in their crystal lattices. Moreover, in the case of the 5-benzyl-6,5'-O-anhydrouridine a significant positional disorder is present with the phenyl rings existing in two orientations. (C) 2015 Elsevier B.V. All rights reserved.
Preparation of C5-substituted O6,5′-cyclouridine
作者:Adam Mieczkowski、Pauline Peltier、Thomas Zevaco、Luigi A. Agrofoglio
DOI:10.1016/j.tet.2009.02.077
日期:2009.5
The synthesis of hitherto unknown C5-substituted O6,5′-cyclouridines is described. The 2′,3′-isopropylidene-uridine was treated with N-halogenosuccinimides forming appropriate bridged 5-halogeno derivatives. Using lithiation method, bromine substituent at C5 position was exchanged into various alkyl and alkenylderivatives.
A mild and efficient approach to the 6H-oxazolo[3,2-f]pyrimidine-5,7-dione scaffold via unexpected rearrangement of 2,3-dihydropyrimido[6,1-b][1,5,3]dioxazepine-7,9(5H,8H)-diones: synthesis, crystallographic studies, and cytotoxic activity screening
We report a mild and efficient approach to the optically pure 6H-oxazolo[3,2-f]pyrimidine-5,7-dione scaffold via the unexpectedrearrangement and ring contraction of 2,3-dihydropyrimido[6,1-b][1,5,3]dioxazepine-7,9(5H,8H)-diones derived from nucleoside precursors. The developed procedure enables the synthesis of a wide range of compounds with great structural diversity. The structure of the obtained
我们报告了通过2,3-二氢嘧啶基[6,1 -b ]的意外重排和环收缩,对光学纯的6 H-恶唑啉[3,2 - f ]嘧啶-5,7-二酮支架进行了温和有效的处理[1,5,3] dioxazepine-7,9(5 H,8 H)-二酮衍生自核苷前体。所开发的方法能够合成具有极大结构多样性的多种化合物。通过NMR光谱和单晶X射线结构分析确认了所获得的化合物的结构。测试了最终产物对一种非癌性(成纤维细胞)和六种不同来源(结肠,神经胶质瘤,乳腺癌,子宫颈,外阴和肺)的癌细胞系的细胞毒性作用。合成的产物是具有类似铅的特性的低分子量化合物,适用于药物化学优化程序。