Synthesis and UV photoelectron investigation of the “peptide units” of α,β-dehydroamino acids
Tóm tắt
The He(I) and He(II) photoelectron (PE) spectra of the N-methylamides of N-acetyldehydroalanine (1) and N-acetyldehydrophenylalanine (2) are presented and discussed, within a comprehensive investigation of the electronic structure and conformation ofα, β-dehydroamino acid derivatives. Three different procedures have been adopted for the synthesis of1. The PE results of the “peptide units” are in tune with theoretical predictions and they support the view that in the vapor phase the tendency towards a planar arrangement around the torsion angle φ is much more marked for N-acetyldehydroalanine-NHR systems than for (Z)-substituted ones.
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