title: Understanding the conformational behaviour of Ac-Ala-NHMe in different media. A joint NMR and DFT study.
abstract: The conformational behaviour of Ac-Ala-NHMe was studied in the gas-phase and in solution by theoretical calculations (B3LYP-D3/aug-cc-pVDZ level) and experimental (1)H NMR. The conformational preferences of this compound were shown to result from a complex interplay between the strengths of possible intramolecular hydrogen bonds, steric interactions, hyperconjugation, entropy effects and the overall dipole moments. The Ac-Ala-N(Me)2 derivative was studied in addition, to design a system akin to Ac-Ala-NHMe, but with disrupted intramolecular hydrogen bonds involving the -NHMe group, mimicking the effect of polar protic solvents.
authors.affiliation: Chemistry Institute, University of Campinas, Campinas, SP 13083-970, Brazil. rittner@iqm.unicamp.br.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Cormanich
authors.forename: Michael
authors.initials: M
authors.lastname: Bühl
authors.forename: Roberto
authors.initials: R
authors.lastname: Rittner
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives* / Q000737:chemistry; D006860:Hydrogen Bonding; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory
chemical_list: C024314:N-acetylalanyl-N-methylamide; D000409:Alanine