Synthesis and restricted furanose conformations of three novel bicyclic thymine nucleosides: a xylo-LNA nucleoside, a 3′-O,5′-C-methylene-linked nucleoside, and a 2′-O,5′-C-methylene-linked nucleoside
作者:Vivek K. Rajwanshi、Ravindra Kumar、Mikael Kofod-Hansen、Jesper Wengel
DOI:10.1039/a901729a
日期:——
The xylo-LNA nucleoside 1-(2-O,4-C-methylene-β-D-xylofuranosyl)thymine (9) and the 2′-O,5′-C-methylene linked nucleoside 1-(2,6-anhydro-β-D-altrofuranosyl)thymine (28) were obtained in overall yields of 13% (8 steps) and 31% (7 steps) starting from furanose derivatives 1 and 21, respectively. In the synthesis of 3′-O,5′-C-methylene-linked nucleoside derivatives, cyclization by intramolecular attack
所述木糖-LNA核苷1-(2- ø,4- Ç亚甲基- β- d -xylofuranosyl)胸腺嘧啶(9)和2'- Ò,5'- Ç -亚甲基连接起来的核苷1-(2,6-从呋喃糖衍生物1和21分别获得13%(8步)和31%(7步)的总产率的脱水-β - D-呋喃呋喃糖基)胸腺嘧啶(28)。在3' - O,5'- C-亚甲基连接的核苷衍生物的合成中,通过3-酮基官能团上6-羟基的分子内攻击进行环化,生成C-3-半缩酮呋喃糖11及其随后转化为核苷15的方法非常有效。这是,然而,不可能以分离脱苄基2'-羟基,2'- ö甲基和2'- ö -叔丁基二甲基衍生物16,18和20分别在分析纯的形式。溶液相的构象分析表明该双环核苷8,9,14,15,17和19,以在N型呋喃糖构象和双环核苷酸主要存在27和28采取的S型构象。