Synthesis and Antinociceptive Activity of Newly Modified Amine Analogs of Phencyclidine in Mice.
Phencyclidine (PCP, I) and its substituted analogs are significant and broadly abused psychotomimetic drugs that affect the central nervous system. They possess many pharmacological properties due to the presence of specific receptors in the brain. Methyl group, despite strong electron-donating and characters of dipole moments, was placed on various positions of phenyl and amine moieties of phencyclidine along with the substitution of benzylamine, piperazine, and aniline derivatives in place of piperidine ring of phencyclidine to create novel compounds of the core with analgesic properties. For evaluation of the analgesic activities of newly synthesized compounds, they were screened by tests of tail immersion (thermal) and formalin (chemical) pains. The obtained data with the control and PCP groups were also compared. The outcomes indicated that some new compounds have more antinociceptive effects than PCP in tail immersion and formalin tests. In the tail immersion test, the methyl piperazine analog (III) shows more efficacy than others. In the formalin test, none of the compounds are as effective as phencyclidine at the earliest time-point, but compounds IV and V show effectiveness during the second stage of formalin pain. It can be concluded that the methyl-piperazine analog of phencyclidine was the best candidate to decrease acute thermal pain, and benzylamine derivatives were suitable candidates to reduce chemical pains.