Premium
NMR‐based conformational analysis of perezone and analogues
Author(s) -
Zepeda L. Gerardo,
BurgueñoTapia Eleuterio,
PérezHernández Nury,
Cuevas Gabriel,
JosephNathan Pedro
Publication year - 2013
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.3940
Subject(s) - chemistry , intramolecular force , vicinal , conformational isomerism , nmr spectra database , side chain , coupling constant , pulsed field gradient , two dimensional nuclear magnetic resonance spectroscopy , stereochemistry , molecule , allylic rearrangement , spectral line , crystallography , computational chemistry , organic chemistry , polymer , physics , particle physics , astronomy , catalysis
Complete assignment of the 1 H NMR chemical shift and coupling constant values of perezone (1), O ‐methylperezone (2) and 6‐hydroxyperezone (3) was carried out by total‐line‐shape‐fitting calculations using the PERCH iterative spectra analysis software (PERCH Solutions Ltd., Kuopio, Finland). The resulting simulated spectra for the three compounds showed strong similarity to their corresponding experimental spectra. Particularly, all vicinal, allylic and homoallylic coupling constant values for the side chain of the three compounds were very similar, thus revealing that the conformation of these three molecules in solution is indeed almost identical. This fact is in agreement with extended side chain conformations over folded chain conformations because 1, 2 and 3 undergo completely different intramolecular cycloaddition reactions. In addition, results of double pulsed field gradient spin echo NOESY 1D experiments performed on perezone (1) were unable to provide evidence for folded conformers. Copyright © 2013 John Wiley & Sons, Ltd.