14301-39-4Relevant articles and documents
Activation energies of aminolysis of aliphatic esters in aprotic media
Tuulmets, Ants,Talvik, Agu-Tonis
, p. 111 - 119 (2007/10/03)
Activation enthalpies and entropies for the third-order aminolysis reaction of n-butyl formate, n-butyl-trichloroacetate and sec-butyl trifluoroacetate were determined in solvents of various polarity and π-basicity. The importance of the steric requirements of the reagents together with high activation entropy values support the assumption of cyclic transition states for the reaction. Electrophilicity of the ester and the solvent properties predetermine the reaction mechanism in the range between the pathway through a zwitterionic intermediate for the formate and the nearly concerted reaction for the trichloroacetate. The negative activation energy of an aminolysis reaction should not necessarily be attributed to a good leaving group, but can be determined by the electrophilicity of the ester and the solvent effects.