N-(4-Methoxybenzyl)-3-phenylpropylamine (CAS no.: ), which is also called as propanamine, N-[(4-methoxyphenyl)methyl]-, could be produced through the following synthesis routes.

A. N-(4-Methoxybenzyl)-2-nitrobenzenesulfonamide (CAS no ). A 300-mL, two-necked, round-bottomed flask equipped with a magnetic stirring bar, nitrogen gas inlet, and a rubber septum is charged with 6.81 g (49.6 mmol) of , 100 mL of dichloromethane and 6.93 mL (49.6 mmol) of triethylamine. The mixture is stirred and cooled in an ice-water bath while 10.0 g (45.1 mmol) of 2-nitrobenzenesulfonyl chloride is added over a period of 5 min. After 5 min, the ice bath is removed and the reaction mixture is allowed to warm to room temperature, stirred for 15 min, and then quenched with 100 mL of 1N hydrochloric acid (HCl). The aqueous layer is extracted with two 100-mL portions of dichloromethane , and the combined organic extracts are washed with 50 mL of brine, dried over magnesium sulfate , filtered, and concentrated under reduced pressure to give 14.2 g (98%) of the crude 2-nitrobenzenesulfonamide . Recrystallization from 500 mL of 1:1 ethyl acetate/hexane gives 13.00-13.15 g (90-91%) of N-(4-Methoxybenzyl)-2-nitrobenzenesulfonamide as white crystals.

B. N-(4-Methoxybenzyl)-N-(3-phenylpropyl)-2-nitrobenzenesulfonamide . A 200-mL, two-necked, round-bottomed flask equipped with a magnetic stirring bar, a nitrogen gas inlet, and a rubber septum is charged with 10.0 g (31.0 mmol) of N-(4-Methoxybenzyl)-2-nitrobenzenesulfonamide, 12.9 g (93.1 mmol) of potassium carbonate, and 40 mL of anhydrous dimethylformamide (DMF). To the stirred mixture is added 5.19 mL (34.1 mmol) of 3-phenylpropyl bromide over a period of 5 min and the resulting mixture is heated in a 60°C oil bath for 70 min. The reaction mixture is allowed to cool to room temperature, diluted with 250 mL of water, and extracted with three 250-mL portions of ether. The combined organic extracts are washed with brine (100 mL), dried over magnesium sulfate , filtered, and concentrated under reduced pressure to give a pale yellow liquid. The residue is purified by column chromatography on silica gel to give 13.5 g (99%) of N-(4-Methoxybenzyl)-N-(3-phenylpropyl)-2-nitrobenzenesulfonamide as a viscous pale yellow liquid.

C. N-(4-Methoxybenzyl)-3-phenylpropylamine (CAS no ). A 100-mL, two-necked, round-bottomed flask equipped with a magnetic stirring bar, nitrogen gas inlet, and a rubber septum is charged with 7.82 mL (76.5 mmol) of thiophenol and 20 mL of acetonitrile (CH₃CN). The mixture is cooled in an ice-water bath and 10.9 M aqueous potassium hydroxide solution (7.02 mL, 76.5 mmol) is added over a period of 10 min. After 5 min, the ice-water bath is removed, and 13.5 g (30.6 mmol) of N-(4-Methoxybenzyl)-N-(3-phenylpropyl)-2-nitrobenzenesulfonamide in 20 mL of acetonitrile is added over 20 min. The reaction mixture is heated in a 50°C oil bath for 40 min. The reaction mixture is allowed to cool to room temperature, diluted with 80 mL of water, and extracted with three 80-mL portions of dichloromethane . The combined organic extracts are washed with brine (80 mL), dried over magnesium sulfate , filtered, and concentrated under reduced pressure. The residue is purified by column chromatography on silica to give 7.81 g of the desired amine and its hydrochloride salt. This oil is dissolved in 120 mL of dichloromethane and washed with two 80-mL portions of 1 M aqueous sodium hydroxide solution, 40 mL of brine, dried over magnesium sulfate , filtered, and concentrated under reduced pressure. Bulb-to-bulb distillation (0.25 mm, oven temperature 150°C) provides 6.98-7.08 g (89-91%) of N-(4-Methoxybenzyl)-3-phenylpropylamine as a colorless oil.