Walczak Dominik, Sikorski Artur, Grzywacz Daria, Nowacki Andrzej, Liberek Beata
Faculty of Chemistry, University of Gdańsk Wita Stwosza 63 80-308 Gdańsk Poland
RSC Adv. 2022 Oct 13;12(45):29223-29239. doi: 10.1039/d2ra04274f. eCollection 2022 Oct 11.
A series of β-d-ribofuranosides and ribonucleosides fused with 2,3--isopropylidene ring was synthesized and studied in terms of their conformational preferences. Based on the H NMR spectra, DFT calculations, and X-ray analysis the -like and -like conformations adopted by these furanosides are identified. The -like and -like conformations are assigned to ribonucleosides without the 2,3--isopropylidene group. The studies are supported by analysis of the structural data of β-d-ribofuranosides and ribonucleosides deposited in the Cambridge Crystallographic Data Center (CCDC) database. Finally, the factors influencing the conformational preferences of the furanose ring with the β-d-ribo configuration are indicated. These are the unfavorable ecliptic orientation of the 2-OH and 3-OH groups, the 1,3-pseudodiaxial interaction of the aglycone and terminal hydroxymethyl group and the -anomeric effect. It is also proved that the -anomeric effect acts in β-d-ribofuranosides.
合成了一系列与2,3-异丙叉环稠合的β-D-呋喃核糖苷和核糖核苷，并对其构象偏好进行了研究。基于核磁共振氢谱、密度泛函理论计算和X射线分析，确定了这些呋喃糖苷所采用的类C2'-内型和类C3'-内型构象。类C2'-内型和类C3'-内型构象被指定给没有2,3-异丙叉基的核糖核苷。这些研究得到了对剑桥晶体学数据中心（CCDC）数据库中β-D-呋喃核糖苷和核糖核苷结构数据的分析支持。最后，指出了影响具有β-D-核糖构型的呋喃糖环构象偏好的因素。这些因素包括2-OH和3-OH基团不利的重叠取向、苷元与末端羟甲基的1,3-假双轴相互作用以及α-异头效应。还证明了α-异头效应在β-D-呋喃核糖苷中起作用。
