[N+:1]([C:4]1[CH:5]=[CH:6][C:7]([N:10]2[CH2:15][CH2:14][NH:13][C:12](=[O:16])[CH2:11]2)=[N:8][CH:9]=1)([O-:3])=[O:2].C[Si]([N-][Si](C)(C)C)(C)C.[Na+].C1COCC1.[CH2:32](Br)[C:33]1[CH:38]=[CH:37][CH:36]=[CH:35][CH:34]=1>CN(C=O)C.O>[CH2:32]([N:13]1[CH2:14][CH2:15][N:10]([C:7]2[CH:6]=[CH:5][C:4]([N+:1]([O-:3])=[O:2])=[CH:9][N:8]=2)[CH2:11][C:12]1=[O:16])[C:33]1[CH:38]=[CH:37][CH:36]=[CH:35][CH:34]=1
To a solution of 4-(5-nitropyridin-2-yl)piperazin-2-one (B-13) (365 mg, 1.64 mmol) in DMF (6 mL) was added, dropwise, 1.0 M sodium bis(trimethylsilyl)amide solution in THF (1.8 mL, 1.8 mmol), followed 1 min later by benzyl bromide (215 μL, 1.8 mmol), also dropwise. After 1 h, the reaction mixture was poured into water and extracted with EtOAc. The extract was dried over Na2SO4, filtered, and concentrated. The crude product was purified by silica gel chromatography (eluant: gradient of EtOAc in hexanes) to give 1-benzyl-4-(5-nitropyridin-2-yl)piperazin-2-one (B-14) (329 mg, 64% yield). MS (M+1): 313.2
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