Synthesis
General procedure for the synthesis of 1-diphenylmethylazetidin-3-one: (Preparative Example 78) To a mixture of 1-diphenylmethylazetidin-3-ol hydrochloride (5.52 g) and triethylamine (27.9 ml) was added slowly and dropwise a dimethylformamide solution (80 ml) of pyridine trioxide complex (19.7 g). The reaction mixture was stirred at 50 °C for 30 min and then cooled to room temperature. The reaction mixture was poured into ice water, extracted with ethyl acetate and the organic layer was washed with brine. Activated carbon (5 g) was added to the organic layer and stirred at room temperature for 3 days. The activated carbon was removed by filtration and the filtrate was concentrated. The residue was dissolved in methanol (200 ml), activated carbon (10 g) was added and stirred at room temperature for 3 days. The activated carbon was removed by filtration again and the filtrate was concentrated. The residue was purified by silica gel column chromatography (eluent: heptane/ethyl acetate = 4:1, then 2:1). The grades containing the target compound were collected and concentrated to give a light yellow oil (3.21 g). Hexane was added to the oily material to induce crystallization and the crystals were collected by filtration. The crystals were dried under ventilated conditions to give the title compound (1.11 g, 23.4% yield). The concentrated residue of the filtrate was added to hexane and left to crystallize at room temperature. After precipitation, the supernatant was removed by pipette and dried under reduced pressure to give the light yellow crystalline title compound (940 mg, 19.8% yield).1H-NMR (CDCl3) δ (ppm): 4.01 (4H, s), 4.60 (1H, s), 7.22 (2H, m), 7.30 (4H, m), 7.48 (4H, m).
References
[1] Patent: US2010/190771, 2010, A1. Location in patent: Page/Page column 38
[2] Journal of Medicinal Chemistry, 2017, vol. 60, # 16, p. 7029 - 7042
[3] Patent: WO2014/68527, 2014, A1. Location in patent: Page/Page column 83; 84
[4] Chemistry Letters, 1999, # 7, p. 605 - 606
[5] Patent: EP1889836, 2008, A1. Location in patent: Page/Page column 78
