A simple and efficient strategy for direct regioselective esterification atO-2 of β-cyclodextrin was developed by using the combination of N,N'-carbonyldiimidazole and carbonate buffer in 1,4-dioxane, which does not require large amounts of polar organic solvents such as DMF, toxic solvents such as CH3CN, or flammable bases such as NaH. Moreover, their hydrolyses by neighboring-group participation were observed. Mono-2-tosyl-β-cyclodextrin was liable to epoxidation, while mono-2-(p-methylbenzoyl)-β-cyclodextrin liable to isomerization. They had different mechanisms of hydrolysis.
使用N,N'-碳
酰亚胺和
碳酸盐缓冲液在
1,4-二氧六环中开发了一种直接选择性酯化β-
环糊精的简单高效策略,该策略不需要大量极性有机溶剂(如
DMF)、有毒溶剂(如CH
3CN)或易燃碱(如NaH)。此外,观察到它们通过邻基参与的
水解作用。单-2-对
甲苯磺酰基-β-
环糊精易于环氧化,而单-2-(对
甲苯甲酰)-β-
环糊精易于异构化。它们具有不同的
水解机制。