Benzodiazepine receptor ligands - III. Synthesis and biological evaluationof 2-and/or 3-substituted pyrazolo[5,1-c][l,2,4]benzotriazine 5-oxides

A new series of 2- and/or 3-substituted pyrazolo[5,1-c][1,2,4]benzotriazine 5-oxides and their 8-chloro derivatives were synthesized, and their benzod iazepine receptor (BZR) affinities were evaluated in vitro in comparison to lead compound 3-ethoxycarbonyl-8-chloropyrazolo[5,1-c][1,2,4]benzotriazine -5-oxide (29) [1,2]. None of the new compounds showed significant affinity for BZR. On the basis of a pharmacophore/receptor model suggested for lead compound 29, some hypotheses to explain the inactivity of new derivatives a re discussed. (C) 1999 Elsevier Science S.A. All rights reserved.