A class of substituted imidazolo[5,1-a]phthalazine derivatives as ligands for
GABAA
receptors of formula I
##STR1##
which are partial or full inverse agonists of an 5 receptor subunit
while being relatively free of activity at 1 and/or 2 and/or 3
receptor subunit binding sites are described herein; they are therefore of benefit
as a medicament for enhancing cognition but with the reduction or elimination of
proconvulsant activity.
