Potent GABAA receptor positive allosteric modulator that acts at the benzodiazepine site (Ki values are 1.2 and 1.7 nM in rat frontal cortex and cerebellum respectively). Displays ~ 10-fold selectivity for α1 subunit-containing receptors (EC50 values are 2.6, 24, 60 and 77 nM for α1β2γ2, α2β2γ2, α3β3γ2 and α5β2γ2 receptors respectively). Exhibits sedative, hypnotic, anxiolytic and anticonvulsant activity in vivo and is orally active. Purity 99%. MW (observed): 376.43