A. Synthesis of (tetrahydrofuran-3-yl)methylamine hydrochloride. A mixture of tetrahydrofuran-3-carbaldehyde (50 wt%, aqueous solution, 5 mL, 25 mmol), ammonium chloride (13 g, 25 mmol), and Ruanne nickel (2 mL slurry) in methanol was placed in a Parr shaker and reacted at 40 °C. Hydrogen was passed through and kept at room temperature for 16 hours. After completion of the reaction, the mixture was filtered through diatomaceous earth and the filtrate was concentrated to obtain an oily substance. To this oily substance was added dioxane (50 mL), 1 M sodium hydroxide solution (50 mL) and di-tert-butyl dicarbonate (5.5 g, 25 mmol). The reaction mixture was stirred at room temperature for 16 hours. After completion of the reaction, extraction was carried out with ethyl acetate and water. The organic layer was dried with magnesium sulfate, filtered and concentrated to give an oil. The oil was purified by silica gel column chromatography (eluent: 0-20% ethyl acetate in hexane solution) to give a clarified oily product. The oily product was treated with a dioxane solution of 4 N HCl. The reaction solution was concentrated and ground with ether to give a white solid product (0.33 g, 10% yield). MS (ESI) m/z 101.9 [M + 1]+.
