Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, 101 Żwirki i Wigury, 02-089 Warszawa, Poland.
College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences (MISMaP), University of Warsaw, 2C Stefana Banacha, 02-097 Warszawa, Poland.
Int J Mol Sci. 2022 Mar 31;23(7):3875. doi: 10.3390/ijms23073875.
Rotamers are stereoisomers produced by rotation (twisting) about σ bonds and are often rapidly interconverting at room temperature. Xylitol-massively produced sweetener-(2,3,4)-pentane-1,2,3,4,5-pentol) forms rotamers from the linear conformer by rotation of a xylitol fragment around the C2-C3 bond (rotamer 1) or the C3-C4 bond (rotamer 2). The rotamers form two distinguishable structures. Small differences in geometry of rotamers of the main carbon chain were confirmed by theoretical calculations; however, they were beyond the capabilities of the X-ray powder diffraction technique due to the almost identical unit cell parameters. In the case of rotamers of similar compounds, the rotations occurred mostly within hydroxyl groups likewise rotations in L-arabitol and D-arabitol, which are discussed in this work. Our results, supported by theoretical calculations, showed that energetic differences are slightly higher for rotamers with rotations within hydroxyl groups instead of a carbon chain.
旋光异构体是由σ键旋转（扭曲）产生的立体异构体，通常在室温下快速互变。木糖醇（大量生产的甜味剂-（2,3,4）-戊烷-1,2,3,4,5-戊醇）通过木糖醇片段围绕 C2-C3 键（旋光异构体 1）或 C3-C4 键（旋光异构体 2）的旋转，从线性构象体形成旋光异构体。旋光异构体形成两种可区分的结构。通过理论计算证实了主碳链旋光异构体的几何形状存在微小差异；然而，由于几乎相同的晶胞参数，X 射线粉末衍射技术无法实现。在类似化合物的旋光异构体的情况下，旋转主要发生在羟基内，同样发生在 L-阿拉伯糖醇和 D-阿拉伯糖醇中，本工作对此进行了讨论。我们的理论计算结果表明，与在碳链内旋转相比，在羟基内旋转的旋光异构体的能量差异略高。
