Abstract

Syntheses are reported for 6-( methylthio, ethylthio, propylthio, substituted benzylthio and chloro )-3-( methoxy, unsubstituted and benzamidomethyl )-2-arylimidazo[1,2-b] pyridazines containing methoxy, methylenedioxy and methyl groups attached to phenyl substituents . In tests of the ability of these compounds to displace [³H]diazepam from rat brain membranes, 3-methoxy-6-(3′,4′-methylenedioxybenzylthio)-2- (3′,4′-methylenedioxyphenyl) imidazo [1,2-b] pyridazine (IC₅₀ 1 nM) bound most strongly; methylenedioxy groups were beneficial to activity whereas polymethoxy or dimethyl substituents were generally detrimental.