Abstract
The synthesis of a series of 6-chloro-3-methoxy(and ethoxy )-2- phenyl[and (variously substituted phenyl), thienyl, and naphthalenyl ] imidazo [1,2-b] pyridazines and a 6-fluoro analogue are reported. These compounds were tested for their ability to displace [3H]diazepam bound to washed rat brain plasma membranes. Under standard assay conditions (see Experimental) and in the presence of 100 μM γ- aminobutyric acid, 6-chloro-3-methoxy-2-(p-tolyl ) imidazo [1,2- b] pyridazine was the most active compound with an IC50 value of 148 nM (cf. diazepam, with IC50 of 4.2 nM).