Kinetic regularities of resolution of amines racemates in the acylation reaction with chiral N-protected amino acids esters

In this work, the kinetic and stereochemical regularities of the kinetic resolution of the 1-phenylethylamine racemate in the acylation reaction under the action of optically active 4-nitrophenyl ester of N-protected phenylalanine in 2-propanol and 1,4-dioxane were studied. Kinetic measurements were carried out using UV spectroscopy. The studies of the reaction series made it possible to establish the reaction orders with respect to the reagents, as well as the kinetic regularities of the enantioselective acylation. It is shown that different kinetic schemes of the reaction take place in protic and aprotic solvents. Based on the experimental data on the reaction kinetics of both the individual enantiomers and the amine racemate, the enantioselectivity values of the acylation are calculated. It has been found that the nature of the solvent and the reagents ratio strongly affect the selectivity of kinetic resolution. Practical recommendations on the conditions of preparative kinetic resolution of amines by amino acid derivatives using the acylation reaction are proposed.