Synthesis and benzodiazepine receptor affinity of pyrazolo[1,5-α]pyrimidine derivatives.: 3.: New 6-(3-thienyl) series as α1 selective ligands

New 3-aryl-6-(3-thienyl)pyrazolo[1,5-alpha]pyrimidin-7-ones (2a-j) are synthesized and evaluated in vitro on Bz/GABA(A) receptors and on recombinant benzodiazepine receptors (alphaxbeta2/3gamma2; x = 1-3, 5) expressed in HEK293 cells. SAR studies on the new compounds are conducted and molecular modeling is accomplished to better investigate requirements leading to subtype selectivity. Some of the synthesized compounds are tested in vivo to explore their pharmacological effect as a consequence of their high alpha1beta2gamma2 subtype selectivity observed in vitro.