Synthesis and pharmacological evaluation of 3-(2-furyl)- and 3-(3-furyl)-(-chloropyrazolo[5,1-c][1,2,4]benzotriazine 5-oxides, new 3-heteroaryl substituted benzodiazepine receptor ligands.

The synthesis of 3-(2-furyl)- and 3-(3-furyl)-8-chloropyrazolo[5,1-c][1,2,4]betizotriazine 5-oxides is reported. The binding affinities at the central Benzodiazepine Receptor (BZR) and the muscle relaxant, anticonvulsant and anxiolytic activities of new furyl derivatives are compared to those of the 3-heteroaryl derivatives, BZR ligands previously reported by us. The results confirm the stringent spatial requisites of the lipophilic pocket that accommodates the 3-substituent, which seems to influence both the binding and intrinsic activity of this new class of ligands.