transN-Methyl-N-[2-(1-pyrrolidinyl)cyclohexyl] cycloprop-2-ene-1-carboxamides: Novel lipophilic kappa opioid agonists

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-pyrrolidinyl)-1-oxaspiro[4.5]dec-8-yl]-2-cyclopropene-1-carboxamide, 13, is a highly lipophilic chemically novel potent selective kappa opioid agonist.