Imidazopyridazine (III) was prepared by condensation of 3-amino-6-chloropyridazine (I) with ethyl 4-chloroacetoacetate (II) in refluxing ethanol. Alkylation of (III) with iodomethane in the presence of NaH furnished the dimethyl derivative (IV). Alternatively, intermediate (IV) was directly obtained by condensation of 3-amino-6-chloropyridazine (I) with ethyl 4-bromo-2,2-dimethyl-3-oxobutanoate (V) in the presence of disodium phosphate. Reaction of the chloroimidazopyridazine (IV) with 3-[4-(diphenylmethoxy)piperidin-1-yl]propanamine (VI) at 200 C provided adduct (VII). The ethyl ester function of (VII) was finally hydrolyzed to the target carboxylic acid employing NaOH.