3-(omega-Aminoalkyl)-5,5-dialkyl(or spirocycloalkyl-1',5-)hydantoins as new 5-HT1A and 5-HT2A receptor ligands

A series of new 3-(omega-aminoalkyl)-5,5-disubstituted hydantoins, containing 1-phenylpiperazine, 1-(o-methoxyphenyl)piperazine or 1,2,3,4-tetrahydroisoquinoline fragments, were synthesized by standard alkylation procedures and their 5-HT1A and 5-HT2A receptor affinities were determined. It has been shown that the investigated derivatives are recognized by 5-HT1A and 5-HT2A receptors due to the presence of a 1-arylpiperazine fragment however, the terminal hydantoin moiety plays an important role in stabilization of the receptor-ligand complex. It has also been found that the two 1-phenylpiperazine derivatives 32 and 36 are new selective 5-HT2A receptor ligands (Ki = 34 and 37 nM, respectively), whereas the derivative of 1-(o-methoxyphenyl)piperazine (38) is a new, highly potent 5-HT1A receptor ligand (Ki = 0.51 nM) with a moderate affinity for 5-HT2A receptors (Ki = 213 nM).