Kinetics of Reversible Endothermic Elimination Reactions: β-Amino Carboxylic Esters and Amides

Article abstract of DOI:10.1021/jo00356a015

The kinetics of the elimination reactions of substituted β-amino carboxylic esters and amides, to give amines and the α,β-unsaturated esters and amides, have been studied in several model systems.The reaction was studied by trapping the olefin formed with another nucleophile capable of competing with the amine formed by elimination.The rate constant for elimination of methyl 3-(N-methyl-N-butylamino)propionate, in methanol at room temperature, is 1.8E-6 s^-1.The corresponding amide has an elimination rate constant 8.8E-8 s^-1.Rate constants for the forward reaction were also measured and combined with the reversion rate constants to yield equilibrium constants for the same two systems.The equilibrium constants for the methyl esters is 2.0E4 L mol^-1 and for the amides is 7.3E3 L mol^-1.These were confirmed by measurement of the equilibrium concentrations of olefins by 1H NMR spectroscopy.