60949-48-6Relevant articles and documents
Base-Catalyzed Acyl Exchange Reactions of N,O-Diacyl-o-aminophenols. Substituent and Temperature Effects on the Equilibrium Constants
Sakurai, Tadamitsu,Nagaoka, Tohru,Kamiya, Jun,Inoue, Hiroyasu
, p. 775 - 778 (2007/10/03)
Substituent and temperature effects on the equilibrium constants for the triethylamine-catalyzed acyl exchange reactions of N-(substituted benzoyl)-O-acetyl-o-aminophenols have been investigated by 1HNMR spectroscopy. It was found that the standard enthalpy change ΔHo in acyl exchange processes, estimated from temperature dependence of the equilibrium constant, correlates well with the standard free energy change ΔGo which was used as a measure of the relative stability of isomer pairs, while the standard entropy change ΔSo is approximately constant (-6±2 J K-1 mol-1) irrespective of the substituems in benzoyl introduced. The finding of enthalpy-controlled acyl exchange reactions confirms that the relative stability of a given isomer pair is determined by the difference in electrostatic force of attraction between the amide nitrogen with a partial positive charge and the ester carbonyl oxygen having a partial negative charge in both isomers.
