1956-08-7Relevant articles and documents
Inhibition of the Hydrolysis of p-Nitrophenyl Esters by Association with an Erythromycin A Derivative
Barra, Monica,Rossi, Rita H. de
, p. 1758 - 1772 (2007/10/02)
The alkaline hydrolysis of p-nitrophenyl esters (1) of an homologous series of straight chain acids and derivatives of naphthoic acids was studied in the presence of the antibiotic erythromycin A (E) and its hydrolysis product (Z).While (E) does not affect the hydrolysis of 1, (Z) inhibits this reaction.The observed pseudo-first-order rate constants decrease as the Z concentration increases and they tend to a minimum value.This inhibition is ascribed to the formation of a host-guest complex between Z and 1.It is suggested that the attack of an external HO- at the carbonyl ester group is hindered by steric and electrostatic effects.The association constants and the second-order rate constants for the complexed esters were calculated.The inhibition tends to be complete for esters of alkyl chains with an add number of carbon atoms.Such a trend is probably related to the geometric requirements of inclusion.
