Reaction of isophthaloyl dichloride (I) with cycloheptylamine (II) in the presence of triethylamine in dichloromethane gives N,N'-dicycloheptylisophthalimide (III), which is reduced with sodium bis(2-methoxyethoxy)aluminum hydride in toluene to yield 1,3-bis(cycloheptylaminomethyl)benzene (IV). Compound (IV) is treated with p-nitrophenylisocyanate (V) to afford 1,3-bis[1-cycloheptyl-3-(4-nitrophenyl)ureidomethyl]benzene (VI), which is reduced with hydrogen in the presence of palladium over charcoal to give 1,3-bis[1-cycloheptyl-3-(4-aminophenyl)ureidomethyl]benzene (VII). Finally, compound (VII) is treated with aqueous formaldehyde and hydrogen in the presence of platinum oxide in ethanol, followed by addition of hydrochloric acid in ethanol.