Cl.[NH:2]1[CH2:5][CH:4]([NH:6][C:7]2[CH:12]=[CH:11][C:10]([Br:13])=[CH:9][C:8]=2[N+:14]([O-:16])=[O:15])[CH2:3]1.C=O.[C:19](O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+]>C(#N)C.C(OCC)(=O)C>[Br:13][C:10]1[CH:11]=[CH:12][C:7]([NH:6][CH:4]2[CH2:5][N:2]([CH3:19])[CH2:3]2)=[C:8]([N+:14]([O-:16])=[O:15])[CH:9]=1To a mixture of azetidin-3-yl-(4-bromo-2-nitro-phenyl)-amine, hydrochloride (27.7 mmol, 8.54 g) in acetonitrile (100 mL) and 37% aqueous formaldehyde (83.0 mmol, 6.28 mL, 3.00 equiv.) at 0° C. add sodium triacetoxyborohydride (88.6 mmol, 18.8 g) slowly. Stir at room temperature under nitrogen overnight. Remove volatiles under reduced pressure. Dilute with ethyl acetate, wash with 10% aqueous sodium bicarbonate twice, dry over anhydrous sodium sulfate, filter, and concentrate under reduced pressure to obtain 8.5 g of an orange solid. Purify on a 120 g silica column eluting with 5% methanol in dichloromethane to obtain the title compound (5.92 g, 75%). LC-MS m/z (79Br/81Br) 286.0/288.0 [M+H]+.
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