天然有机化合物的质谱研究(Ⅶ)——直链邻二醇类化合物构型的确定

Studies on Mass Spectrometry of Natural Products(Ⅶ)--Determination of Configuration of Some Acyclic Glycols

用硼酸三甲酯作反应试剂,以反应质谱法研究某些直链邻二醇类化合物的构型。实验结果表明:凡苏式构型的样品与硼酸三甲酯反应产生的特征离子丰度比均大于赤式构型的样品与其反应所产生的特征离子丰度比。由此可方便地利用反应质谱法来鉴别该类化合物的苏、赤式构型。

There are a lot of studies on the stereochemistry of cyclic glycols by means of mass spectrometry,but the studies on the relative configurations of acyclic glycols by MS have not been found in literatures.This paper presents that the relative configurations of some acyclic glycols were firstly determined by Reaction Mass Spectrometry(RMS)using trimethyl borate as reagent.In five pairs of three-and erythro-isomers studied,there are no characteristic differences between their routine chemical ionization mass spectra.But in their reaction mass spectra,the relative abundance ratio,r,of characteristic ion,[Ms+Mn+H-2CH_(3)OH]+,to reference ion,[Ms+H-H_(3)O]+,produced by the glycols of threo-configuration was much greater than that produced by erythro-isomers.Based upon this fact,we can distinguish the relative configurations between a pair of stereoisomeric acyclic glycols.And these phenomena were explained in virtue of the principles of stereochemistry.