The Friedel-Crafts condensation of 1-acetyl-2,3,4,5-tetrahydro-1H-1-benzazepine (I) with 3-(1-acetylpiperidin-4-yl)propionyl chloride (II) by means of AlCl3 in 1,2-dichloroethane gives 3-(1-acetylpiperidin-4-yl)-1-(1-acetyl-2,3,4,5-tetrahydro-1H-1-benzazepin-8-yl)-1-propanone (III), which is deacetylated in refluxing concentrated aqueous HCl yielding 3-(piperidin-4-yl)-1-(2,3,4,5-tetrahydro-1H-1-benzazepin-8-yl)-1-propanone (IV). Finally, this compound is benzylated with benzyl bromide (V) and K2CO3 in ethanol affording the final product as free base, which is then treated with fumaric acid in MeOH/CH2Cl2.