Selective and potent analgetics derived from cannabinoids

Based on the hypothesis that analgetic activity is a dissociable feature of the cannabinoid molecule, we examined modifications of the side chain, the phenolic moiety, and, most significantly, structures that lack the benzopyran functionality present in THC and (--)-9-nor-9 beta-hydroxyhexahydrocannabinol (HHC). A new grouping, the 1-methyl-4-phenylbutyloxy C-3 side chain, elaborates a unique lipopholic region. Replacement of the phenol substituent produced several derivatives which retain analgetic activity in the codeine potency range. Introduction of a weakly basic nitrogen at C-5 and deletion of the axial methyl group in the B ring, two structural changes forbidden by traditional cannabinoid SAR, resulted in a unique family of benzoquinolines with potent analgetic activity. The prototype of this series, levonantradol, exhibits potent and stereospecific analgetic and antiemetic activity.