Imidazo[1,2-b]pyridazines. XXIII Some 5-Deaza Analogues. Syntheses of Some 2-Aryl-6-(chloro, methoxy or unsubstituted)-3- (variously substituted)imidazo[1,2-a]pyridines and Their Affinity for Central and Mitochondrial Benzodiazepine Receptor

Abstract

The syntheses of ethyl {2′-aryl-6′-(chloro, methoxy and unsubstituted)imidazo[1,2-a]pyridin-3′-yl}-2- (acylamino, acetoxy and hydroxy)acetates, 3-benzamidomethyl-2-benzoyl-6-(chloro and methoxy)imidazo-[1,2-a]pyridines, 3-amino-6-chloro-2-phenylimidazo[1,2-a]pyridine and ethyl 2-(2′-phenylimidazo[1,2-a]pyridin-3′-yl)acetate are reported. The ability of these compounds to displace [³H]diazepam from central and mitochondrial (peripheral-type) benzodiazepine receptors has been examined. Ethyl 2-benzamido-2-{6′-chloro-2′-(4′′-chlorophenyl)imidazo[1,2-a]pyridin-3′-yl} acetate (21) was selective for peripheral-type receptors (IC₅₀13 nM) but none bound strongly to central receptors.