Synthesis and study the analgesic effects of new analogues of ketamine on female wistar rats.

Ketamine (2-o-chlorophenyl-2-methylaminocyclohexan, CAS 1867-66-9, CI-581, Ketalar, I), a potent derivative of Phencyclidine (1-[1-phenylcyclohexyl] piperidine, CAS 956-90-1, PCP, II), and many of its analogues have shown anesthetic and analgesic effects. In this research, new derivatives of I, (2-[p-methoxybenzylamino]-2-[p-methoxyphenyl] cyclohexanone, ket-OCH3, III), (2-[p-methylbenzylamino]-2-[p-methoxyphenyl] cyclohexanone, ket-CH3, IV) and their intermediates (V-VIIII) were synthesized and the acute and chronic pains of III and IV were evaluated on rats using tail immersion (as a model of acute thermal pain) and formalin (as a model of acute and chronic chemical pain) tests. The results werecompared with ketamine and control (saline) groups. The results indicated that in tail immersion and formalin tests, these new derivatives (III and IV) were usually effective for decreasing pain on rats.