Synthesis and evaluation of pharmacological properties of some new xanthone derivatives with piperazine moiety.

A series of new xanthone derivatives with piperazine moiety [1-7] was synthesized and evaluated for their pharmacological properties. They were subject to binding assays for α₁ and β₁ adrenergic as well as 5-HT₁A, 5-HT₆ and 5-HT₇b serotoninergic receptors. Five of the tested compounds were also evaluated for their anticonvulsant properties. The compound 3a 3-methoxy-5-{[4-(2-methoxyphenyl)piperazin-1-yl]methyl}-9H-xanthen-9-one hydrochloride exhibited significantly higher affinity for serotoninergic 5-HT₁A receptors (Ki=24 nM) than other substances. In terms of anticonvulsant activity, 6-methoxy-2-{[4-(benzyl)piperazin-1-yl]methyl}-9H-xanthen-9-one (5) proved best properties. Its ED₅₀ determined in maximal electroshock (MES) seizure assay was 105 mg/kg b.w. (rats, p.o.). Combining of xanthone with piperazine moiety resulted in obtaining of compounds with increased bioavailability after oral administration.