Molecular recognition of isomeric protonated amino acid esters monitored by ESI-mass spectrometry

• Andrea Liesenfeld and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 825–831, doi:10.3762/bjoc.10.78

• acid derivatives. The performance of the receptors was evaluated by ESI-mass spectrometry using the isomer labelled guest method (ILGM). This method revealed the preferred binding of L-norleucine and L-leucine compared to L-isoleucine for both receptors. Furthermore, non-covalent isotope effects

• protonated amino acid esters. Keywords: amino acids; isomer labelled guest method (ILGM); mass spectrometry; molecular recognition; 9,9’-spirobifluorenes; template; Introduction The separation of constitutionally isomeric amino acids is of practical interest. This is particularly true for leucine (Leu

• use of isotopically labelled substrates in the sense of an isomer labelled guest method (ILGM) (Figure 3) which is closely related to the enantiomer labelled guest method (ELGM) introduced by Sawada [22]. Here, a competitive recognition experiment using a non-labelled substrate and a mass-labelled