Atomic Electrostatic Potential as a Descriptor of Aminolysis of Phenyl and Thiophenyl Acetates and Hydrolysis of Acetanilides

Abstract

Hydrolysis of acetanilides and aminolysis of phenyl and thiophenyl acetates are related reactions since these are processes of nucleophilic substitution on the carbonyl carbon. Current views of chemical reactivity based on the DFT theory rely upon reactivity indices that are descriptors of both the reaction center and the molecule as a whole, and have not been applied to the given processes before. One of such descriptors is an atomic electrostatic potential. The given parameter was calculated by the DFT theory M06/6-311+G (non-specific solvation, MeCN, SMD, and full optimization) for the structures of substituted phenyl acetates XPhO-C(O)Me, acetanilides XPhNHC(O)Me, thiophenyl acetates ZPhSC(=O)Me, and benzyl amines XPhСH2NH2 (X, Z substituents). It has been found that all relationships between the atomic electrostatic potential, the charge on the reaction center in the Hirshfeld scheme, and logK are symbatic. Consequently, in all of the cases, the rate is determined by the nucleophilic attack on the reaction center, with the activity/selectivity relationship being observed. The fact that the reaction rate is limited by the nucleophilic attack of the reagent is not inconsistent with the views of the reaction being concerted, since it is known that such reactions may be quite concerted though not quite synchronous.