A series of new 1-(heterocyclyalkyl)-4-(propionanilido)-4-piperidinyl methyl esters and methylene methyl ethers have been synthesized and pharmacologically evaluated. In the mouse hot-plate test, the majority of compounds exhibited an analgesia (EDm< 1 mg/kg) superior to that of morphine. These studies revealed a pharmacological accommodation for many more structurally diverse and far bulkier aromatic ring systems than the ...
