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E-Journal of Chemistry
Volume 9, Issue 3, Pages 1562-1568
http://dx.doi.org/10.1155/2012/398683

Direct Regioselective Esterification at O-2 of β-Cyclodextrin and Hydrolysis by Neighboring-group Participation

Ningxia Engineering Research Center for Hui Medicine Modernization, School of Pharmacy, Ningxia Medical University, Yinchuan, Ningxia, 750004, China

Received 6 January 2010; Accepted 1 March 2011

Copyright © 2012 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A simple and efficient strategy for direct regioselective esterification at O-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.