Self-Inclusion Complexes Derived from Cyclodextrins:  Synthesis and Characterization of 6A,6B-Bis-O-[p-(allyloxy)phenyl]-Substituted β-Cyclodextrins

• Published in: Journal of organic chemistry Vol. 61; no. 25; pp. 8949 - 8955
• Main Authors: Chen, Zhen, Bradshaw, Jerald S, Yi, Guoliang, Pyo, Dongjin, Black, Delbert R, Zimmerman, S. Scott, Lee, Milton L, Tong, Weida, D'Souza, Valerian T
• Format: Journal Article
• Language: English
• Published: American Chemical Society 13.12.1996
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo960679i

The syntheses, structures, and spectroscopic properties of 6A,6B-bis-O-[p-(allyloxy)phenyl]-substituted β-cyclodextrins have been investigated. Selective activation of the 6A,6B-hydroxy groups was carried out by treating heptakis(2,3-di-O-methyl)-β-cyclodextrin (1) with 2,4-dimethoxybenzene-1,5-disulfonyl chloride to give 6A,6B-bissulfonate ester 2 in a yield of only 3%. This material was treated with sodium p-(allyloxy)phenoxide in DMF to form 6A,6B-bis-O-[p-(allyloxy)phenyl]-heptakis(2,3-di-O-methyl)-β-cyclodextrin (3), which had two isomers. One (3A) has the two p-(allyloxy)phenyl arms directed away from the cyclodextrin cavity, and the other (3B) has one of the p-(allyloxy)phenyl groups through the cavity to form a self-inclusion complex. When either 3A or 3B was treated with methyl iodide and sodium hydride, the resulting permethylated 6A,6B-bis-O-[p-(allyloxy)phenyl]heptakis(2,3-di-O-methyl)-6C,6D,6E,6F,6G-penta-O-methyl-β-cyclodextrin (4) was composed of two isomers, in which 4B is a self-inclusion complex. 3A and 3B also can be converted into a mixture of 3A and 3B in strong base but not when melted in the absence of base. 4A and 4B do not isomerize. Detailed 1D and 2D NMR spectroscopic studies were carried out to characterize the structures of these new compounds, and molecular mechanics techniques were used to explain the experimental facts.