STRUCTURE-ACTIVITY RELATIONSHIP STUDIES ON THE 5-HT1A RECEPTOR AFFINITY OF PHENYL-4-[OMEGA-(ALPHA-TETRALINYL)ALKYL]PIPERAZINE OR -PHENYL-4-[OMEGA-(BETA-TETRALINYL)ALKYL]PIPERAZINE .4.

The synthesis of 1-phenylpiperazines, linked in the alpha or beta posi tion of the tetralin moiety on the terminal part of the N-4 alkyl chai n, and their radioligand binding affinities for 5-HT1A, 5-HT2A, D-1, D -2, alpha(1), and alpha(2) receptors along with SAR studies on the 5-H T1A receptor are reported. Several changes have been carried out on pr evious structures of type 2, by inserting the alkyl chain with variabl e length in the alpha or beta position of the tetralin moiety and by c hanging the position of the methoxy group on the aromatic ring of the tetralin nucleus. The highest affinity (IC50 = 0.50 nM) and selectivit y for the 5-HT1A receptor were showed by 1-phenylpiperazine 2a with a three-membered alkyl chain bearing a 5-methoxytetralin-1-yl ring in th e omega position.