Synthesis and antifertility activity of omega-chain phenyl- and 16-phenoxy-analogues of (+/-)-11-deoxyprostaglandin F1 alpha.

Some omega-chain phenyl- and 16-phenoxy- analogues of (+/-)-11-deoxyprostaglandin F1 alpha have been synthesized and evaluated for anti-fertility activity in the hamster. 11-Deoxy-16-phenoxy-17,18,19,20-tetranor-PGF1 alpha was the most active member of the series with an ED50 equal to that of PGF2 alpha. 11-Deoxy-17-phenyl-18,19,20-trinor-PGF1 alpha, which was one third as active as PGF2 alpha, was more potent than the corresponding 16- and 18-phenyl compounds. Aryl ring substitution was found to lower activity, except that with the 16-phenyl compound, p-bromo and m-trifluoromethyl substitution increased the potency. The antifertility activity of the phenoxy compounds, which were poor substrates for 15-hydroxyprostaglandin dehydrogenase, was shown to correlate well with the binding affinity for the bovine corpus luteum PGF2 alpha receptor. Some quantitative structure-activity data supporting this finding are presented.