Design and synthesis of aralkyl-ketone piperazine derivatives and their antalgic activities

To synthesize aralkyl-ketone piperazine derivatives as analgesic agents, the N atom of the one side of piperazine ring is protected by formyl group firstly, then the unprotected N atom is alkylated to prepare aralkyl-ketone piperazine derivatives. Their analgesic biological activities were well studied by mice writhing model，rat hot plate model and rat tail flick model. Sixty four compounds were synthesized and pharmacological tests in vivo revealed these compounds have potent analgesic activities, especially compound I₁₂, I₁₄, I₂₁ and I37. These four compounds are more worthy for further research.