1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (0.41 g, 2.14 mmol) was added to a solution of 2-(4-aminobutyl)-7-methoxy-1,2,3,4-tetrahydroisoquinoline (0.5 g, 2.14 mmol), 4-(3-cyanophenyl)benzoic acid (0.368 g, 2.14 mmol) and 1-hydroxybenzotriazole (0.1 g, 0.7 mmol) in dichloromethane (8 ml). The resultant mixture was shaken for 18 h. before saturated aqueous potassium carbonate (5 ml) was added and shaking continued 1 hr. The organic layer was chromatographed on silica gel using 10-100% ethyl acetate-hexane gradient elution to afford the title compound as a yellow gum (0.57 g, 61%).
