Opioid properties of some derivatives of pethidine based on tropane

Abstract

The preparation of some tropane analogues of pethidine and its reversed ester, chiefly with preferred 3 alpha-m-hydroxyphenyl chair conformations, is described. The former were secured from tropan-3-one in a sequence of reactions involving cyanide attack, hydrolysis, Grignard attack and then rearrangements. The reversed ester was obtained by treating tropan-3-one with lithium phenyl, followed by acylation. Configurational and conformational assignments follow from NMR analysis. The antinociceptive potencies of these compounds in mice are reported, and discussed in relation to non-phenolic congeners and the 4-arylpiperidine moiety of morphine.