Reaction of 1-aminophthalazines with alpha-halocarbonyl compounds: imidazo[2,1-a]phthalazines and their benzodiazepine receptor activities.

The one-pot synthesis and the benzodiazepine receptor binding activity of some imidazo[2,1-a]phthalazines bearing different substituents at position-2 and/or 3 and/or 6 is reported. The dissimilar binding results of the reported compounds are discussed in relation to the nature and/or position of the substituents on the tricyclic ring system.