Benzyl isocyanate → N'-Benzyl-N-[[4-[[(2-pyridinylmethyl) amino]methyl]phenyl]methyl]-N-(5,6,7,8-tetrahydro-8-quinolinyl)-urea

To a stirred solution of N-(2-nitrobenzenesulfonyl)-N-(2-pyridinylmethyl)-N′-[5,6,7,8-tetrahydro-8-quinolinyl]-1,4-benzenedimethanamine (140 mg, 0.257 mmol) in dichloromethane (5 ml) cooled to 0° C. was added dropwise, benzyl isocyanate (0.035 mL, 0.284 mmol). The reaction mixture was then allowed to stir at room temperature for two hours. The mixture was evaporated and the residue was purified by column chromatography on silica gel (3% methanol in dichloromethane as eluent) to afford the desired urea in an 81% yield.