基于DMP氧化和HWE反应的半乳糖修饰

Glycoside Modification Based on DMP Oxidation and HWE Reaction

为更好地将前沿新知识、新理论、新技术和新方法应用于高年级本科综合实验教学环节,设计了基于Dess-Martin(DMP)氧化和Horner-Wadsworth-Emmons(HWE)反应的双丙酮半乳糖的修饰实验。通过调研醇的氧化和醛的烯基化的方法设计实践方案,通过过氧硫酸氢钾复合盐(oxone)氧化邻碘苯甲酸制备2-碘酰基苯甲酸(IBX),在乙酸和乙酸酐作用下将其转化为DMP,再利用DMP实现双丙酮半乳糖的氧化,最后通过HWE反应实现可差向异构醛的烯基化。运用多种显色方法的薄层色谱分析(TLC)技术对反应进程进行监测,利用Schlenk技术实现无水无氧操作,通过柱层析技术分离纯化目标产物,化合物的结构和纯度通过红外光谱、核磁共振波谱和高分辨率质谱得到了表征。DMP氧化具有条件温和、操作简单、产率和选择性高以及低毒性等优点。设计方案的实践内容比较丰富,具有较强的设计性和综合性,有利于实现学生知识、能力和素质的有机融合,培养学生解决复杂问题的综合能力和高级思维。

To better integrate cutting-edge knowledge,theories,technologies,and methods into senior undergraduate comprehensive experimental courses,this paper designed an experiment involving the modification of diacetone-D-galactose based on Dess-Martin(DMP)oxidation and Horner-Wadsworth-Emmons(HWE)reactions.We established experimental procedures by researching the oxidation of alcohols and the alkenylation of aldehydes.2-iodoacylbenzoic acid(IBX)was synthesized by oxidizing o-iodobenzoic acid with potassium peroxymonosulfate(oxone).This was then transformed into DMP under the influence of acetic acid and acetic anhydride.DMP was subsequently employed to oxidize diacetone-D-galactose,and the HWE reaction was finally used to achieve the differential isomeric aldehyde alkenylation.The progress of the reaction was monitored using thin-layer chromatography(TLC)with various staining methods.Schlenk technique was adopted for anhydrous and anaerobic operations,and the target products were isolated and purified through column chromatography.The structure and purity of the compounds were characterized using infrared spectroscopy,nuclear magnetic resonance spectroscopy,and high-resolution mass spectrometry.DMP oxidation has the advantages of mild conditions,simple operations,high yield and selectivity,and low toxicity.The designed experimental procedures are comprehensive,rich in content,and emphasizes integrative nature,which is beneficial for the organic integration of students’knowledge,capabilities,and qualities,while cultivating their ability to tackle complex problems and develop advanced thinking skills.