Bifunctional catalysis of ester aminolysis - A computational and experimental study

Article abstract of DOI:10.1002/jlac.199619961003

Various pathways for the reaction of methylamine with methyl acetate catalyzed by 2(1H)-pyridone have been investigated at the Becke3LYP/6-31G**//HF/6-31G** level of theory. The most favorable pathway consists of a one-step reaction, in which all bond-forming and -breaking processes occur in concert. These modeling studies also show the pyridone to function as an acid, which led to the investigation of several substituted pyridones. 4-Cyano-, 3-cyano-6-methyl-, and 3-cyano-2(1H)-pyridone have indeed been shown to provide better catalysis in the ester aminolysis reaction by ab initio modeling at the Becke3LYP/6-31G**//HF/3-21G level. In order to verify the theoretical results, the catalytic activities of various substituted 2-pyridones in the reaction of n-butylamine with p-nitrophenyl acetate in chlorobenzene solution have been determined. The observed catalytic rate constants are indeed in agreement with the theoretical predictions. Other catalyst characteristics such as solubility and state of aggregation are, however, also of paramount importance in this reaction. VCH Verlagsgesellschaft mbH, 1996.