M. Jedrzejczak et al., KINETICS OF AMINOLYSIS OF SOME BENZOYL FLUORIDES AND BENZOIC ANHYDRIDES IN NON-HYDROXYLIC SOLVENTS, Perkin transactions. 2, (7), 1994, pp. 1471-1479
The kinetic form of the spontaneous aminolysis of benzoyl fluorides in
non-hydroxylic solvents is unlike that reported for the other benzoyl
halides, but is similar to that found for the aminolysis of esters. V
ariations on the mechanisms currently advocated for ester aminolysis a
re suggested for the benzoyl fluoride reactions. Tetrahedral intermedi
ates are likely, but their rate-determining breakdown to products may
involve a simultaneous proton transfer to the leaving fluoride ion. Th
e kinetic behaviour differs from that found for aqueous solutions. The
kinetics of the spontaneous aminolysis of benzoic anhydrides by prima
ry amines, and by morpholine, in dioxane solution are first-order in e
ach reagent over a wide amine concentration range, but the aminolysis
by imidazoles involves also an important kinetic term second-order in
amine. The mechanistic implications are discussed. Again the observati
ons differ from some of those reported for aqueous solutions. For amin
olyses of a variety of acylating agents, kinetic observations using no
n-hydroxylic solvents show that the easier it is for the leaving group
to depart, owing to the structure of the acylating agent and/or that
of the attacking amine, the less important become paths involving two
or more amine molecules, but that such paths are generally more import
ant than they are in hydroxylic solvents.