Heterocyclic and piperonylic acid esters of 1-methyl-4-piperidinol as analgesics.

Heterocyclic and piperonylic acid esters of 1-methyl-4-piperidinol were synthesized and evaluated for analgesic activity. 1-Methyl-4-piperidinol 4-piperonylate (14) exhibited activity in the codeine range (mouse hot plate). In monkeys, 14 acted neither as a typical narcotic agonist nor as a typical antagonist and it showed no physical dependence liability of the morphine type. The nonquaternary C-4 peperidinol esters 1a, 4, 8, and 14 exhibited marginal to virtually no binding to the opiate receptor in rat brain homogenates. The interaction of various functional groups of this series with potential binding sites of a nonopiate type receptor is discussed.