Imidazo[1,2-b]Pyridazines. XIX. Syntheses and Central Nervous System Activities of Some 6-Arylthio(aryloxy and alkylthio)-3-(acetamidomethyl, benzamidomethyl, methoxy and unsubstituted)-2-arylimidazo[1,2-b]pyridazines

Abstract

Some 6-arylthio( aryloxy and alkylthio )-3-( acetamidomethyl , benzamidomethyl, methoxy and unsubstituted )-2-arylimidazo[1,2-b] pyridazines have been prepared and examined for their ability to displace [3H]diazepam from rat brain membranes. The most active compound was 3-acetamidomethyl-2-(3',4'-methylenedioxyphenyl)-6-phenylthioimidazo[1,2-b] pyridazine with IC50 4.4 nM. The 3-acylaminomethyl-6-(2- and 3-methoxyphenylthio)-2-phenylimidazo[1,2-b] pyridazines proved less active than their 6-phenylthio analogues, and larger substituents at the 2- and 6-positions markedly decreased binding. Significant differences in binding ability have been observed between 3-acylaminomethyl-2-aryl-6-phenylthioimidazo[1,2-b] pyridazines and the corresponding imidazo [1,2-a]pyridines.