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Amphetamine sulfate (2.34 g, 0.0133 mole) was treated with 2N sodium hydroxide solution and dichloromethane to give free amphetamine (1.8 g). A mixture of this amphetamine (1.80 g, 0.0133 mole), ethyl 5-bromovalerate (2.78 g, 0.0133 mole) and diisopropylethylamine (3.45 g, 0.0266 mole) was refluxed in dry benzene for 10 hours. The cooled solution gave a precipitate of hydrobromide salt of diisopropylethylamine, which was removed by suction filtration. The filtrate was washed with water, dried with anhydrous sodium carbonate and evaporated to dryness. The oil (3.20 g) obtained was separated by preparative TLC (silica gel, 5% methanol -- 95% ether). Each fraction was extracted with methanol. The extracts were dried with anhydrous sodium carbonate and evaporated to dryness to give oils. One fraction (Rf 0.45) gave a colorless oil (1.44 g) of N-(4'-ethoxycarbonylbutyl) amphetamine in 41% yield.