Abstract: Structurally-defined, low molecular weight oligomers and preparation thereof which are active in the protection of oxidative physphorylation of mitochondria and exhibit ionophoretic activity. Said structurally defined low molecular weight oligomers are synthesized using a modified 15-dehydro PGB.sub.1 such as 16,16-dimethyl-15-dehydro prostaglandin B.sub.1 as a precursor to obtain oligomeric mixtures which are structurally defined and active in the protection of oxidative phosphorylation and exhibit ionophoretic activity. Synthesis of modified 15-dehydro-PGB.sub.1 ; 16,16-dimethyl-15-dehydro-prostagalandin B.sub.1 ; is also described.