Azaflavones compared to flavones as ligands to the benzodiazepine binding site of brain GABAA receptors

A series of azaflavone derivatives and analogues were prepared and evaluated for their affinity to the benzodiazepine binding site of the GABAA receptor, and compared to their flavone counterparts. Three of the compounds, the azaflavones 9 and 12 as well as the new flavone 13, were also assayed on GABAA receptor subtypes (α1β3γ2s, α2β3γ2s, α4β3γ2s and α5β3γ2s), displaying nanomolar affinities as well as selectivity for α1- versus α2- and α3-containing receptors by a factor of between 14 and 26.