IMIDAZO[1,2-B]PYRIDAZINES .17. SYNTHESIS AND CENTRAL-NERVOUS-SYSTEM ACTIVITY OF SOME 6-(ALKYLTHIO AND CHLORO)-3-(METHOXY, UNSUBSTITUTED ANDBENZAMIDOMETHYL)-2-ARYIMDAZO[1,2-B]PYRIDAZINES CONTAINING METHOXY, METHYLENEDIOXY AND METHYL SUBSTITUENTS

Syntheses are reported for 6-(methylthio, ethylthio, propylthio, subst ituted benzylthio and chloro)-3-(methoxy, unsubstituted and benzamidom ethyl)-2-arylimidazo[1,2-b]pyridazines containing methoxy, methylenedi oxy and methyl groups attached to phenyl substituents. In tests of the ability of these compounds to displace [H-3]diazepam from rat brain m embranes, thoxy-6(3',4'-methylenedioxybenzylthio)-2-(3'',4'' -methylen edioxyphenyl)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.