Synthesis of a series of polyunsaturated fatty acids, their potencies as essential fatty acids and as precursors of prostaglandins†

A series of polyunsaturated fatty acids has been tested on essential fatty acid activity and as precursors of prostaglandins. It was confirmed that biological activity of all-cis 8,11,14-trienoates and 5,8,11,14-tetraenoates is restricted to acids with 19, 20 or 21 carbon atoms. All-cis 8,11,14-eicosapolyenoates with extra double bonds at positions 2, 3 or 4 are also biologically active, On the other hand, an additional double bond in the ω-chain of the molecule, e.g. at the 18th position, leads to nearly complete loss of activity.