Determination of absolute configuration of salvic acid, an ent-labdane from Eupatorium salvia, by vibrational circular dichroism.
The relative stereochemistry at C13 and the absolute configuration of salvic acid, a constituent of the leaves of Eupatorium salvia, were established as the 13-(R)-ent-labdane 1. The results follow from vibrational circular dichroism measurements of the derived O-methyl ether methyl ester 3 which were compared to DFT B3LYP/DGDZVP calculated spectra. The relative stereochemistry of salvic acid at C13 was independently verified by single crystal X-ray diffraction measurements of 1, and of its derived diol 4.
Instituto de Ciencias Químicas, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
Marcelo A
MA
Muñoz
Alejandro
A
Urzúa
Javier
J
Echeverría
Maria A
MA
Bucio
Angelina
A
Hernández-Barragán
Pedro
P
Joseph-Nathan
D002942:Circular Dichroism; D004224:Diterpenes / Q000737:chemistry* / Q000302:isolation & purification*; D036602:Eupatorium / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D013237:Stereoisomerism
D004224:Diterpenes; C433017:labdane; C576147:salvic acid