882402-12-2

882402-11-1

882402-12-2

Step 2: Preparation of 2-aminomethyl oxetane: 2-(phthaloylmethyl)oxetane (product of step 1, 19 g, 87.5 mmol) was dissolved in ethanol (250 ml) followed by addition of hydrazine hydrate (6.56 g, 131.2 mmol). The reaction mixture was heated to reflux and maintained for 30 min. After completion of the reaction, the precipitate was collected by filtration. A small amount of Raney Ni (catalyst type W-2) was added to the filtrate and the reaction was continued at reflux for 1.5 hours. At the end of the reaction, the filtrate was filtered to remove inorganic solid impurities. The filtrate was carefully concentrated under reduced pressure to give the crude product. The crude product was purified by vacuum distillation to collect a colorless liquid fraction (3.63 g, about 47% yield) with a boiling point of 55-60 °C/30 mbar. The product contained ethanol and DMF residues and could be used directly in subsequent reactions without further purification.