Effect of linking bridge modifications on the 5-HT1A receptor activity of some 4-(omega-benzotriazol-1-yl)alkyl-1-(2-methoxy-phenyl)piperazines.

A new series of arylpiperazines with two (2a-4a) and four (2c-4c) methylene spacers was synthesized. Compounds 2a, 2c, 3c, 4a and 4c were found to be 5-HT1A ligands (Ki = 4-88 nM). The most promising compound, 2c, bound with the highest affinity (Ki = 4 nM) at 5-HT1A sites. The results of in vivo experiments showed that compounds 2a-4a were inactive, while 2c-4c revealed a distinct antagonistic activity towards postsynaptic 5-HT1A receptors. The pharmacological profile of the tested compounds was discussed in comparison with that of the three methylene analogs b, described earlier.