The synthesis and kappa opioid agonist activities of some lipophilic analogues of the kappa opioid agonist U-50488 incorporating motifs bearing two aromatic rings in place of the 3, 4- dichlorophenyl group are described. Trans 2, 3-diphenyl-N-methyl-N [2-(1-pyrrolidinyl) cyclohexyl]-2-cyclopropene-1-carboxamide, 7, is a potent kappa opioid agonist. A diphenylcyclopropene analogue of CI-977, trans 2, 3-diphenyl-N-methyl-N-[7-(1- ...