Abstract
Cis-Eicosapenta-5:8:ll:14:17-enoic acid was isolated from South African pilchard oil by the techniques of lithium salt-acetone segregation, urea-complex fractionation, molecular distillation and reversed-phase partition chromatography. Some properties of this acid were determined. The position of the double bond nearest to the carboxyl group was definitely determined by using an Arndt-Eistert synthesis in combination with a method of oxonolytic degradation. This procedure is probably of wide applicability. The degree of purity of the acid was critically considered.