A new, simple method has been developed for the methylation of cyclodextrins. The reaction proceeds in the heterogeneous phase with dimethyl sulphate, using a solvent in which the original cyclodextrins and the bases used are poorly soluble or insoluble. However, in the presence of phase transfer catalysts, methylation proceeds with good yields. The products are mixtures of randomly methylated cyclodextrins (RAMEB), containing 60-70% of heptakis(2,6-di-O-methyl)-β-cyclodextrin (DIMEB), 10-15% of heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TRIMEB) and some monomethylated isomers. These methylated products have proved to be excellent detergents; e.g., they are able to significantly increase the water solubility of hydrocortisone, methyltesterone, etc. On repeating methylation twice, the amount of TRIMEB increases, and a pure product (28% yield) can be obtained by crystallisation.
|Number of pages||8|
|Journal||Journal of Inclusion Phenomena and Molecular Recognition in Chemistry|
|Publication status||Published - szept. 1 1994|
ASJC Scopus subject areas
- Food Science
- Condensed Matter Physics