Diastereoselective gas-phase ion/molecule reactions of ethanolamine neurotransmitter/amido[4]resorcinarene adducts

Fourier-Transform Ion Cyclotron Resonance (FT-ICR) kinetic experiments, supported by molecular mechanics calculations and molecular dynamics simulations, indicate that the relative stability of the diastereomeric proton-bound adducts between some ethanolamine neurotransmitters and a chiral amido[4]resorcinarene receptor depends on the relative position and orientation of the hydroxyl and amino functionalities on the neurotransmitter side chain, on the presence of the methyl substituent on its N center, as well as on the specific group of the receptor proton-bonded to the amino group of the ethanolamine. These factors strongly influence the nature and the intensity of the noncovalent interactions in the ethanolamine/amido[4]resorcinarene adducts and, therefore, their reactivity towards 2-aminobutane enantiomers.