Synthetic nucleic acid secondary structures containing the four stereoisomers of 1,4-bis(thymine-1-yl)butane-2,3-diol
作者:Mikkel S. Christensen、Andrew D. Bond、Poul Nielsen
DOI:10.1039/b713888a
日期:——
of the double-headed acyclic nucleoside 1,4-bis(thymine-1-yl)butane-2,3-diol were incorporated in the central position of four 13-mer oligonucleotides. The phosphoramidite building blocks were synthesized in four or six steps from either D- or L-2,3-O-isopropylidenethreitol. Two epimeric and fully deprotected double-headed nucleosides were analyzed by X-ray crystallography. The incorporation into oligonucleotides
将双头无环核苷1,4-双(胸腺嘧啶-1-基)丁烷-2,3-二醇的四个立体异构体并入四个13-mer寡核苷酸的中心位置。亚磷酰胺结构单元是由D-或L-2,3-O-异丙基亚乙基苏糖醇以四步或六步合成的。通过X射线晶体学分析了两个差向异构和完全脱保护的双头核苷。位阻和环状磷酸酯的形成阻碍了寡核苷酸的掺入。使用吡啶鎓氯化物作为活化剂以及基于31P NMR的偶联和去三苯甲基化过程的动力学分析导致寡核苷酸的产率提高。与(S)-GNA单体相比,发现四种立体异构体之一显示出类似的DNA双链体失稳现象,表示可以引入额外的碱而不会产生热量损失。发现另一种立体异构体可诱导DNA:RNA三向连接的热稳定。因此,该无环双头核苷基序的立体化学很重要,表明了设计人工核酸二级结构的潜力。