Effect of cyclodextrins on the hydrolysis of amides

ALEJANDRO M. GRANADOS; RITA H. DE ROSSI

AMER CHEMICAL SOC

Lugar: Washington; Año: 1993 vol. 58 p. 1771 - 1771

he hydrolysis of p-nitrotrifluoroacetanilide (11, trifluoroacetanilide (21, m-nitrotrifluoroacetanilide (31, and p-nitroacetanilide (4) was studied in the presence of cyclodextrins. The reactions of 1 are catalyzed by a-cyclodextrin (a-CD) and 8-cyclodextrin (8-CD) and also by (hydroxypropy1)cydodextrin (HPCD). The hydrolysis of 4 is catalyzed by 8-CD. The reaction of 2 is inhibited by 8-CD and so is the reaction of 3 by HPCD. Compounds 1 and 4 form two types of inclusion complexes with 8-CD, a 1:l and a 1:2 substrakcyclodextrin complex. Both types of complexes react faster than the free substrate, and for I at pH = 7 all the catalysis is due to the reaction of the 1:2 complex since the 111 complex reacts at about the same rate as the free substrate. The results are explained in terms of two mechanisms: one which involves the acylation of CD by the amides and another which predominates at neutral pH where the two cyclodextrins complexing the substrate stabilize the