Aminimides as Potential CNS Acting Agents. I. Design, Synthesis, and Receptor Binding of 4'-Aryl Aminimide Analogues of Clozapine as Prospective Novel Antipsychotics

A series of substituted 1-[4-(8-chloro-5H-dibenzo[b,e][1,4]diazepin-11-yl)-1-methylhexahydropyrazin-1-ium]-1-aminimide derivatives were designed on the basis of the physicochemical properties of the aminimide functional group and synthesized as potential antipsychotic agents for the treatment of schizophrenia. The target compounds were readily prepared in two steps from clozapine (8-chloro-11-(4-methylpiperazino)-5H-dibenzo[b,e][1,4]diazepine) and involved N-acylation of a common hydrazinium salt intermediate by an acyl chloride or activated ester in the presence of a strong base. The aminimides were tested for in vitro activity at the dopamine D4 and serotonin 5-HT2A receptors and were found to possess modest affinity for both receptor systems.