Imidazo[1,2-b]pyridazines. IV. Syntheses and Central Nervous System Activities of Some 3-Methoxy-6-phenoxy(Substituted Phenoxy and Naphthyloxy)-2-phenylimidazo[1,2-b]pyridazines

Abstract

Syntheses are reported for some 3-methoxy-6-phenoxy(substituted phenoxy and naphthyloxy )-2-phenylimidazo[1,2-b] pyridazines; they were made in order to study their possible pharmacological activity in the mammalian central and peripheral nervous system.

In initial biological screens to detect compounds with potential activity at receptors for the benzodiazepine class of drugs, the most active compounds were 3-methoxy-6-(2′-methylthiophenoxy)- and 6-(2′-dimethylaminophenoxy )-3-methoxy-2-phenylimidazo[1,2-b] pyridazine. Their respective IC₅₀ values for displacement of ³H-diazepam (IC₅₀ for unlabelled diazepam, 4.2 nM ) from rat brain plasma membranes (measured in the presence of 100 μM GABA) were 112 and 149 nM.