Ester hydrolysis by a 2-naphthylacetyl-substituted γ-cyclodextrin

Abstract

In comparison with native cyclo-octa-amylose (γ-cyclodextrin, γ-CD), a modified γ-CD (1), bearing an O-2-naphthylacetyl substituent, produced larger overall ester hydrolysis rates in water (pH 8.7). A 12- fold increase was observed for p-nitrophenyl acetate, arising from both an increased rate of intracomplex hydrolysis and stronger binding, and an 11 -fold increase for m-nitrophenyl acetate, arising from stronger binding. The results were presumed to be due to spacer effects of the appended naphthalene moiety which narrows the large γ-CD cavity. The behaviour of compound (1) was compared with that of cyclohepta-amylose (β-cyclodextrin, β-CD) bearing the same substituent.