Enantioselective influence of cyclodextrins on cleavage of chiralic esters

Assessing the reactivity of optical antipodes is of central importance in drug research. Using the model of 2-methoxy-2-phenylacetic acid-4-nitrophenylester (MPE), the rate of hydrolysis in the presence of beta-cyclodextrin (CD), hydroxyethyl- and hydroxypropyl-beta-CD, as well as methyl-beta-CD is studied photometrically and by means of HPLC (Chiralcel-OD-R-column). Both beta-CD and hydroxyalkylated-beta-CD catalyze (-)-(R)-enantiomers to a larger extent than (+)-(S)-enantiomers, resulting in an enrichment of the latter. Methyl-beta-CD stabilizes the ester trifold, thus abolishing chiral discrimination. (C) 1995 Wiley-Liss, Inc.