Quantum chemical interpretation of reactivities of aliphatic amines and α-amino acids in acylation

Quantum chemical calculations of geometrical, electronic, and energy characteristics for aliphatic amines, ammonia, some alpha-amino acids, and 4-nitrophenyl benzoate (4-NPB) have been performed. By the QSPR method, it was found that the rate constants for the reactions of amino compounds specified with 4-NPB in water-propan-2-ol solvent mixture are linearly dependent on the contribution of the 2p(z)-AO of nitrogen into the HOMO, as well as on the population of the 2p(z)-AO of nitrogen. Different character of the dependencies for 6h-amino acids and aliphatic amines can be explained by their involvement into formation of solvato-complexes with different reactivity.