Synthesis of 9,12‐Dioxo‐10(Z)‐dodecenoic acid, a new fatty acid metabolite derived from 9‐hydroperoxy‐10,12‐octadecadienoic acid in lentil seed (Lens culinaris medik.)

The previously unknown linoleic acid peroxidation product 9,12-dioxo-10(Z)-decenoic acid (Z5) was detected in lentil seed flour (Lens culinaris Medik.) by electron impact mass spectrometry (EI-MS) after derivatization with pentafluorobenzyl-hydroxylamine-hydrochloride, methylation of acidic groups with diazomethane, and protection of hydroxylic groups with N-methyl-N-trimethylsilyl-trifluoroacetamide. The structure of the natural product was confirmed by synthesis of Z5, 9,12-dioxo-l0(E)-decenoic acid, and derivatives. EI-MS, nuclear magnetic resonance and gas chromatographic data of these compounds and synthetic intermediates are discussed.