Discovery of a potent and selective agonist of the prostaglandin EP4 receptor

Abstract Analogues of PGE 2 wherein the hydroxycyclopentanone ring has been replaced by a lactam have been prepared and evaluated as ligands for the EP 4 receptor. An optimized compound ( 19a ) shows high potency and agonist efficacy at the EP 4 receptor and is highly selective over the other seven known prostaglandin receptors.