A mixture of N-benzyl-N'-[3-(3-piperidinomethylphenoxy)propyl]ethanediimidamide trihydrochloride (4.73 g; 9.16 mmoles) [prepared in Step A], 45 ml of CH2Cl2 and 3.8 ml of triethylamine was treated with N,N'-thiobisphthalimide (DMF solvate) (3.64 g; 9.16 mmoles) and stirred for one hour. The mixture was washed with 44 ml of 10% KOH, dried (MgSO4), filtered, diluted with toluene and concentrated. The residue was chromatographed by flash chromatography on 110 g of silica gel (230-400 mesh) using ethyl acetate as the eluent to give 3.1 g (77%) of the title compound. Treatment of the product with an equivalent amount of aqueous HCl in 2-propanol gave the hydrochloride salt of the title compound, mp 138°-141° C.
