NMR-based conformational analysis of perezone and analogues
Por:
Zepeda L.G., Burgueno-Tapia, E, Pérez-Hernández N., Cuevas G., Joseph-Nathan P.
Publicada:
1 abr 2013
Resumen:
Complete assignment of the 1H 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.
Filiaciones:
Zepeda L.G.:
Departamento de Química Orgánica, Escuela Nacional de Ciencias Biolõgicas, Prolongaciõn de Carpio y Plan de Ayala, Col. Santo Tomás, México, D.F. 11340, Mexico
Pérez-Hernández N.:
Escuela Nacional de Medicina y Homeopatía, Instituto Politécnico Nacional, Guillermo Massieu Helguera 239, Col. Residencial La Escalera, Mexico, D.F., 07320, Mexico
Cuevas G.:
Univ Nacl Autonoma Mexico, Inst Quim, Mexico City 04510, DF, Mexico
Joseph-Nathan P.:
Departamento de Química, Centro de Investigaciõn y de Estudios Avanzados Del Instituto Politécnico Nacional, Apartado 14-740, México, D.F., 07000, Mexico
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