Benzodiazepine receptor ligands -: Part II.: Synthesis and biological evaluation of pyrazolo[5,1-c][1,2,4]benzotriazine 4-oxide

A new series of 3-, 8-substituted pyrazolo[5,1-c][1,2,4]benzotriazine 4-oxides 3 were synthesized and their benzodiazepine receptor (BZR) affinities were evaluated in vitro in comparison with their 5-oxide isomers 2. The 4-oxide compounds 3c,m,n,o showed a better receptor affinity than their corresponding 5-oxide isomers, with an efficacy trend of antagonist/partial inverse agonist. From a structure-affinity relationship point of view some insight in the role played by N-4 and Id-oxide is gained. (C) Elsevier, Paris.