The general procedure for the synthesis of methyl azetidine-3-carboxylate hydrochloride from methyl 1 -diphenylmethylazetidine-3-carboxylate was as follows (Preparative Example 85): methyl 1 -diphenylmethylazetidine-3-carboxylate (3.57 g) was dissolved in methanol (360 ml), and ethyl acetate solution of 4N hydrochloric acid (12.7 ml) was added, and the reaction system was maintained at 20 °C. Subsequently, palladium hydroxide (3.57 g) was added as a catalyst and the reaction was stirred at room temperature and under pressurized hydrogen atmosphere (0.4 MPa) for 11 hours. After completion of the reaction, the catalyst was removed by filtration and washed with methanol and water. The filtrate was concentrated to give the crude product of methyl azetidine-3-carboxylate hydrochloride, which presented as a light yellow oil. The reaction was assessed to be quantitative and 1.93 g of product was obtained, which can be used directly in subsequent reactions. The product was detected by ESI-MS, m/z: 116 [M + H]+.
