(-)-3-Isothujone, a small nonnitrogenous molecule with antinociceptive activity in mice.

(-)-3-Isothujone and (+)-3-thujone were examined for antinociceptive activity using the hot-plate and Nilsen tests. In the hot plate test (-)-3-isothujone (ED50 = 6.5 mg/kg) was found to be codeine-like and equipotent with (-)-delta9-tetrahydrocannabinol while the racemic material was essentially half as potent as the levoratatory isomer. (+)-3-Thujone was inactive in both antinociceptive tests as were several structural analogues of the 3-thujones. As with the THC's less antinociceptive activity was observed in the Nilsen test than in the hot-plate assay. Acute toxicities for the 3-thujones were determined and vastly improved synthetic procedures have been developed for two long-known but difficulty accessible 3-thujanols.