The interaction of p-cyclodextrin with propanolol hydrochloride was shown by NMR to produce diastereomeric pairs observable in D,O solution at 400 MHz. By addition of racemate to pure ( -)-isomer, the usefulness of this novel technique in being able to measure optical purity in water down to the 1% level was demonstrated. Using changes in chemical shifts and NOE effects, a possible structure for the inclusion complex is proposed. y-Cyclodextrin induced larger shifts in the spectrum than the p-equivalent, whereas a-cyclodextrin had no effect.

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