title: Phenylalanine and tyrosine methyl ester intramolecular interactions and conformational analysis by (1)H NMR and infrared spectroscopies and theoretical calculations.
abstract: Amino acid conformational analysis in solution are scarce, since these compounds present a bipolar zwitterionic structure ((+)H3NCHRCOO(-)) in these media. Also, intramolecular hydrogen bonds have been classified as the sole interactions governing amino acid conformational behavior in the literature. In the present work we propose phenylalanine and tyrosine methyl ester conformational studies in different solvents by (1)H NMR and infrared spectroscopies and theoretical calculations. Both experimental and theoretical results are in agreement and suggest that the conformational behavior of the phenylalanine and tyrosine methyl esters are similar and are dictated by the interplay between steric and hyperconjugative interactions.
authors.affiliation: Chemistry Institute, University of Campinas, P.O. Box 6154, 13083-970 Campinas, Brazil.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Cormanich
authors.affiliation: Chemistry Institute, University of São Paulo, P.O. Box 26077, 05508-900 São Paulo, Brazil.
authors.forename: Lucas C
authors.initials: LC
authors.lastname: Ducati
authors.affiliation: Chemistry Institute, University of Campinas, P.O. Box 6154, 13083-970 Campinas, Brazil.
authors.forename: Cláudio F
authors.initials: CF
authors.lastname: Tormena
authors.affiliation: Chemistry Institute, University of Campinas, P.O. Box 6154, 13083-970 Campinas, Brazil. Electronic address: rittner@iqm.unicamp.br.
authors.forename: Roberto
authors.initials: R
authors.lastname: Rittner
mesh_terms: D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D010649:Phenylalanine / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: C040444:tyrosine methyl ester; D014443:Tyrosine; D010649:Phenylalanine
keywords: (1)H NMR spectroscopy; Amino acid methyl ester derivatives; Conformational analysis; Infrared spectroscopy; Intramolecular hydrogen bonding; Stereoelectronic effects