The discovery of a novel and potent benzodiazepine receptor pharmacophore

1-(Indol-5-yl)pyrido[2,3-b]imidazoles and 1-(indol-5-yl)benzimidazoles (1) have been found to be unique, novel templates for potent benzodiazepine receptor affinity. The “molecular switch” for this activity lies in the imidazole N3 atom: replacement of this nitrogen for carbon [i.e., as in 5-(indol-1-yl)indoles (2)] affords compounds devoid of affinity for the benzodiazepine receptor (Figure 1).