Synthesis and antifertility activity of 13-aza 14-oxo-prostaglandins

Some 13-aza-14-oxo prostaglandin analogues of PGF2 alpha, PGE2 and PGA2 have been synthetized in optically active form, starting from Corey's intermediate and evaluated for antifertility activity in the hamster. The C-15 absolute configuration was established and found critical for the biological activity, but unexpectedly the highest potency was always associated with the 15 epi derivatives. Among the PGF2 alpha analogues the 15 epi derivative was about one tenth as potent as PGF2 alpha. The preparation of a few 16-phenoxy 17,18,19,20 tetranor-derivatives led to more potent compounds with the p-fluorophenoxy analogue having the same potency as PGF2 alpha.