Imidazo[1,2-b]Pyridazines. XXI. Syntheses of Some 3-Acylaminomethyl-6-(chloro, fluoro, methoxy, methylthio, phenoxy and phenylthio)-2-(phenyl, 4-t-butylphenyl, 4-cyclohexylphenyl, β-naphthyl and styryl)imidazo[1,2-b]pyridazines and Their Interaction With Central and Peripheral-Type Benzodiazepine Receptors