Saccharide (2,4-dichlorophenoxy)acetylhydrazones, the mechanism of heterocyclization under acetylative conditions
作者:El Sayed H. El Ashry、Yeldez El Kilany、Abdallah A. Abdallah、Kamel Mackawy
DOI:10.1016/0008-6215(83)88242-1
日期:1983.3
geometric isomers. Reaction of the pentaacetate with boiling acetic anhydride caused its acetylative heterocyclization into 3-acetyl-5-[(2,4- dichlorophenoxy)methylene]-2-(1,2,3,4,5-penta- O -acetyl- d - galacto -pentitol-1-yl)- 1,3,4-oxadiazoline. A generalized mechanism for the heterocyclization, based on “soft” and “hard” acids and bases, is discussed. d - arabino -Hexos-2-ulose 2-(2,4- dichlorophenoxy)acetylhydrazone
摘要描述了许多单糖的(2,4-二氯苯氧基)乙酰基hydr的合成。研究了相应的d-半乳糖衍生物与乙酸酐在吡啶中的反应。通过肼与五-O-乙酰基-醛-d-半乳糖的反应制备了五-O-乙酰基-醛-d-半乳糖(2,4-二氯苯氧基)乙酰基hydr,其1 Hn.mr光谱表明其存在为两个几何异构体。五乙酸盐与沸腾的乙酸酐反应导致其乙酰化杂环化成3-乙酰基-5-[(2,4-二氯苯氧基)亚甲基] -2-(1,2,3,4,5-戊基-O-乙酰基-d -半乳糖-戊醇-1-基)-1,3,4-恶二唑啉。讨论了基于“软”和“硬”酸和碱的通用杂环化机理。d-阿拉伯-Hexos-2-ulose 2-(2,