Template effects. 7. Large unsubstituted crown ethers from polyethylene glycols: Formation, analysis, and purification
作者:Chiara Antonini Vitali、Bernardo Masci
DOI:10.1016/s0040-4020(01)80080-6
日期:1989.1
tri- to deca-ethylene glycol yields not only the corresponding crown ethers but also higher cyclooligomers that can be analyzed up to about [60] crown-20 by glc: in particular [36] crown-12 and [48] crown-16 were obtained from tetraethylene glycol and purified by column chromatography on cellulose; iii) the reaction, as applied to commercial mixtures of polyethylene glycols (from PEG 200 to PEG 1000)
通过聚乙二醇与甲苯磺酰氯和二恶烷中的异相 KOH 反应,不仅可以获得从 [12] 冠-4 到 [24] 冠-8 的冠状物,还可以获得一些较大的同系物。系统调查表明:i) [27] 冠-9 和 [30] 冠-10 可分别由壬醛和十醛乙二醇形成,并以纯形式分离;ii) 从三乙二醇到十乙二醇的整个聚乙二醇系列不仅产生相应的冠醚,还产生更高的环低聚物,这些低聚物可以通过 GLC 分析至约 [60] 冠-20:特别是 [36] 冠-12 和 [48] 冠-16 是从四乙二醇中获得的,并通过纤维素柱色谱纯化;iii) 该反应应用于聚乙二醇的商业混合物(从 PEG 200 到 PEG 1000)时,在大环尺寸区域也能得到相当高的冠醚产率。讨论了 K+ 离子的模板效应和环寡聚化反应对各种环尺寸的贡献。