Base-catalyzed acyl exchange reactions of N, O-diacyl-o-aminophenols - Effects of an acyl group on the relative stability of acyl-exchanged isomer pair

Abstract

The reaction of N-acyl-o-aminophenol with 1-naphthoyl chloride in the presence of triethylamine gave N-(1-naphthoyl)-O-acyl derivative, while the same product was obtained from the reaction between N- (1-naphthoyl) -o-aminophenol and acyl chloride (RCOC1 : R = CH2OEt, CH2OPh, or OCH2 Ph). The hydrazinolysis of the product revealed that the equilibrium between acyl-exchanged isomers lies almost completely in favor of N- (1-naphthoyl) -O-acyl-o-aminophenol. This interesting result was explained on the basis of the strong electron-donating ability of an oxygen atom incorporated into the substituent R as well as of the electrostatic model of exchanged isomer pair.