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.