Antagonists of serotonin 5-HT6 receptors. III. Pyridine-substituted 3-(phenylsulfonyl)pyrazolo[1,5-a]pyrimidines: synthesis and structure – activity relationship

In continuation of studies on 3-(phenylsulfonyl)pyrazolo[1,5-a]pyrimidine derivatives as 5-HT 6 receptor antagonists, new compounds with a pyridine moiety in the 5and/or 7-position were obtained and their antagonistic activity was screened. It was established that the introduced pyridine changed the 5-HT 6 activity. Some of the obtained 5-pyridin-3-yl-3-(phenylsulfonyl)pyrazolo[1,5-a]pyrimidines 5-HT 6 receptor antagonists with K i = 0.2 – 4.5 nM had therapeutic significance for the treatment of some CNS diseases.