Dialkylaminoalkylnaphthalenes as novel opioid-like analgesics

The study of dialkylaminoalkylnaphthalenes as novel opioid-like analgesics is reported. In particular, the synthesis of (1R,2R/1S,2S)-1-ethyl-1-[2-(6-hydroxynaphthyl)]-1-hydrox-2-m ethyl-2-dimethylaminoethane and its structural analogue (1R,2R/1S,2S)-1-ethyl-1-[2-(6-fluoronaphthyl)]-1-hydroxy-2-methyl- 2-dimethylaminoethane and the configurational analysis by X-ray and 1H NMR spectroscopy are described. Pharmacological profiles are discussed on the basis of the experimental results of analgesia tests (hot plate and writhing test) and rota-rod test, which was performed to distinguish analgesia from drug-induced motor changes. The compounds showed dose-dependent antinociception, with less potency than morphine. Motor coordination appeared to be less involved.