Pyrrole esters of tropanols and related structures as analgesics.

2,4,5-Trimethylpyrrole-3-carboxylic acid esters of tropanols and related monocyclic amino alcohols were synthesized and evaluated for analgesic activity by the mouse hot-plate and Nilsen methods. 1-Methyl-4-piperidinol 4-(2,4,5-trimethylpyrrole-3-carboxylate) (7) exhibited activity in the morphine--codeine range (mouse hot plate). In monkeys, 7 acted neither as a typical narcotic agonist nor as a typical antagonist and it showed no physical dependence liability of the morphine-type. Whereas the pethidine and prodine analgesics have quaternary phenyl substituion at C-4 of the piperidine ring, compound 7 does not.