Novel interphenylene derivatives of 11,12-secoprostaglandins are prepared by the stepwise alkylation of the ethyl ester or the t-butyl ester of acetoacetic acid. One such method involves treatment of the t-butyl ester of acetoacetic acid with a strong base to form the anion followed by treatment with ethyl p-(3-bromopropyl)benzoate to produce ethyl 4-(4-tert-butoxycarbonyl-5-oxo-hexyl)benzoate, subsequently reacting the anion of the thus-formed benzoate with 1-chloro-4-acetoxynonane to produce ethyl 4-(4-acetyl-4-tert-butoxycarbonyl-8-acetoxytridecyl)benzoate followed by decarboxylation and alkaline hydrolysis to produce the desired product 4-(4-acetyl-8-hydroxytridecyl)benzoic acid which is useful as a pharmaceutical in the treatment of patients with renal failure and in the prevention of transplant rejection.