IMIDAZO[1,2-B]PYRIDAZINES .23. SOME 5-DEAZA ANALOGS - 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 RECEPTORS

The syntheses of ethyl {2'-aryl-6'-(chloro, methoxy and unsubstituted) imidazo[1,2-a]pyridin-3'-yl}-2- (acylamino, acetoxy and hydroxy) aceta tes, 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 abili ty of these compounds to displace [H-3]diazepam from central and mitoc hondrial (peripheral-type) benzodiazepine receptors has been examined. Ethyl 2-benzamido-2-{6'-chloro-2'-(4 '-chlorophenyl)imidazo[1,2-a]pyr idin-3'-yl}acetate (21) was selective for peripheral-type receptors (I C50 13 nM) but none bound strongly to central receptors.