Azabicycloalkanes as Analgetics. VI. 5-Phenyl-2-azabicyclo [3, 2, 1] octanes

As part of a study on the structure-activity relationships of the partial agonist activity of phenylazabicycloalkane analgetics, the title compound (I), a five membered alicyclic analog of the known analgetic agent (II), has been synthesized. The aminoketone (V) was converted to I via the 8-oxo derivative (VII) by the usual method. Alternatively, intramolecular Michael reaction of the amino cyclopentenone derivative generated in situ by hydrolysis of the urethane (X) gave the 6-oxo derivative (XII) convertible also to I. Finally and most conveniently, the keto enamines (XVI and XVII), obtained by mercuric acetate oxidation of XIV and XV, were cyclized to XVIII and XII by heating them with aqueous acetic acid, respectively. I was found to be analgetically inactive but exhibited narcotic antagonsit activity comparable to pentazocine. Certain structural correlations between I and other phenylazabicycloalkane analgetics are discussed.