Synthesis and 13C-NMR Spectroscopy of Methylated beta-Cyclodextrins

The methylated analogues of ß-cyclodextrin dissolve in cold water 10 – 20 times better than ß-cyclodextrin itself, however, quite unusually on heating they crystallize from the solution. The structure of heptakis-(2,6-di-O-methyl)- and heptakis-(2,3,6-tri-O-methyl)-ß-cyclodextrin was proved by gas-liquid chromatographic and ¹H-NMR and ¹³C-NMR spectroscopic investigations. The corresponding model compounds were synthetized and, according to ¹³C-NMR spectroscopic investigations, a part of the so far published NMR assignations have to be corrected.