Stereochemistry of α‐parinaric acid fromImpatiens edgeworthii seed oil

Abstract
α-Parinaric acid is a major constituent fatty acid (48%) fromImpatiens edgeworthii Hook F. seed oil. Partial hydrazine reduction of the tetraene gave products which permit defining the stereochemistry of α-parinaric acid. Its structure iscis-9,trans-11,trans-13,cis-15-octadecatetraenoic acid. The tetraene readily reacts with maleic anhydride to give the Diels-Alder product with notrans-unsaturation. The formation of this adduct is contrary to previous reports.