N,N-disubstituted piperazines: synthesis and affinities at alpha4beta2(*) and alpha7(*) neuronal nicotinic acetylcholine receptors.

A series of N,N-disubstituted piperazines were prepared and evaluated for binding to alpha4beta2(*) and alpha7(*) neuronal nicotinic acetylcholine receptors using rat striatum and whole brain membrane preparations, respectively. This series of compounds exhibited selectivity for alpha4beta2(*) nAChRs and did not interact with the alpha7(*) nAChRs subtype. The most potent analogues were compounds 8b and 8f (K(i)=32 microM). Thus, linking together a pyridine pi-system and a cyclic amine moiety via a piperazine ring affords compounds with low affinity, but good selectivity for alpha4beta2(*) nicotinic receptors.