854 mg of 4-(diphenylmethoxy)-1-piperidinepropanamine and 554 mg of 3-tert-butyl-6-chloro[1,2,4]triazolo[4,3-b]pyridazine were dissolved in 10 ml of 1-butanol; 0.91 ml of N-ethyldiisopropylamine was added, followed by refluxing under heating for 21 hours. After cooling, ethyl acetate was added; the reaction mixture was washed with saturated aqueous sodium bicarbonate and saturated saline and dried over magnesium sulfate. After concentration under reduced pressure, the residue was subjected to silica gel column chromatography and eluted with ethyl acetate-methanol-triethylamine (50:5:1). The desired fraction was collected and concentrated under reduced pressure; 780 mg of the residue was dissolved in ethanol; a solution of 282 mg of fumaric acid in ethanol was added, followed by concentration under reduced pressure. The residue was crystallized from ethanol-ethyl acetate (1:5), washed with ethyl acetate, and dried, to yield 938 mg of the title compound.
