Separation and identification of ximenynic acid isomers in the seed oil ofSantalum spicatum R.Br. as their 4,4‐dimethyloxazoline derivatives

The seed oil ofSantalum spicatum contains a significant amount of ximenynic acid,trans‐11‐octadecen‐9‐ynoic acid, a long‐chain acetylenic fatty acid, as a major component (34%). The identity oftrans‐ximenynic acid was confirmed after isolation by ultraviolet, infrared, and nuclear magnetic resonance (NMR) (1H‐ and13C‐) spectroscopy and by gas chromatography/mass spectrometry (GC/MS). Thecis isomer of ximenynic acid was also found (<1%) in some samples. Thecis andtrans isomers were characterized by GC/MS comparison of their methyl esters and 4,4‐dimethyloxazoline derivatives.