A solution of 19.020 g (78.839 mmol) of N-[2-(3-furyl)ethyl]phthalimide and 5.74 ml (118 mmol) of hydrazine monohydrate in 200 ml of ethanol was refluxed for 1 hour. After cooling to room temperature, the reaction mixture was poured into aqueous sodium hydroxide and extracted with dichloromethane 3 times. The combined organic layer was dried over anhydrous magnesium sulfate; the solvent was distilled off under reduced pressure. The resulting crude 2-(3-furyl)ethylamine was dissolved in 150 ml of dichloromethane; a solution of 22.4 g (102 mmol) of di-tert-butyl dicarbonate in 50 ml of dichloromethane was added dropwise at room temperature, followed by stirring for 0.5 hours. The solvent was distilled off under reduced pressure; the resulting crude product was purified by silica gel column chromatography (hexane/ethyl acetate=15/1 to 6/1) to yield N-tert-butoxycarbonyl-2-(3-furyl)ethylamine as a mixture with di-tert-butyl dicarbonate.
