Synthesis and anti-ulcer activity of 16-phenoxy analogues of (+)-11-deoxyprostaglandin E1

Synthesis and gastric antisecretory properties of allenic 16-phenoxy-omega-tetranor prostaglandin E analogs

In order to improve the modest oral activity of PGE2 as an inhibitor of gastric acid secretion, analogs were prepared and tested orally in histamine-challenged rats. Insertion of a double bond at C-4, resulting in the 4,5-allene analog of PGE1, gave a small increase in activity. Introduction of the omega-tetranor-16-phenoxy lower sidechain, a modification known to enhance activity in the PGF series, gave an eight-fold increase in activity. The analog having both modifications (enprostil, 2) showed a six hundred-fold increase in oral antisecretory activity over PGE2, which may reflect a potentiation effect. Modification of enprostil at C-1 (various esters) and at C-11 (11-methyl, 11-deoxy) generally resulted in compounds of high activity while modifications at other sites generally resulted in significant reductions in activity.

Uterine stimulant action of some 16-phenoxy analogues of (+)-11-deoxyprostaglandin E1

Some (+)-11-deoxy-16-phenoxyprostaglandin E1 analogues have been evaluated as uterine stimulants in the anaesthetised pregnant rat. Gastrointestinal side effects, assessed by the antagonism of morphine-induced constipation in the mouse, were relatively low with some of these compounds, six of which had a much more favourable relative selectivity than 16,16-dimethyl-PGE2 methyl ester.