Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/68829
Type: Artigo de periódico
Title: H-1 NMR and theoretical studies on the conformational equilibrium of tryptophan methyl ester
Author: Duarte, CJ
Cormanich, RA
Ducati, LC
Rittner, R
Abstract: Selected (3)J(HH) coupling constants and theoretical calculations were used to explain the conformational equilibrium of L-tryptophan methyl ester (Trp-OMe) in several solvents. The obtained (3)J(H alpha H beta) values did not exhibit any significant variability and thus indicate that there are no conformational population variations for the side chain of the Trp-O-Me depending on the solvent. Moreover, the potential energy surfaces obtained at the B3LYP/cc-pVDZ theoretical level produced eight energy minima that were analysed by QTAIM and NBO methods. It was possible to conclude that the Trp-OMe conformational preferences were due to hyperconjugative effects involving the nonbonding electron pairs of the main chain nitrogen atom and certain antibonding orbitals (sigma(C4-C13)*, sigma(C1-C4)* and sigma(C4-H12)*) and also to the steric effects from the nonbonding electron pairs of oxygen atoms and the main and side chain of this system. (C) 2013 Elsevier B.V. All rights reserved.
Subject: Tryptophan methyl ester
Conformational analysis
Hydrogen bonding
Stereoelectronic interactions
Country: Holanda
Editor: Elsevier Science Bv
Rights: fechado
Identifier DOI: 10.1016/j.molstruc.2013.07.024
Date Issue: 2013
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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