[Br-].[CH2:2]([N+:9]1[CH:14]=[CH:13][CH:12]=[C:11]([CH3:15])[C:10]=1[CH2:16][NH:17][C:18]([O:20][C:21]([CH3:24])([CH3:23])[CH3:22])=[O:19])[C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1.[BH4-].[Na+]>CO>[CH2:2]([N:9]1[CH2:14][CH2:13][CH:12]=[C:11]([CH3:15])[CH:10]1[CH2:16][NH:17][C:18](=[O:19])[O:20][C:21]([CH3:24])([CH3:23])[CH3:22])[C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1To a solution of 1-benzyl-2-(((tert-butoxycarbonyl)amino)methyl)-3-methylpyridin-1-ium bromide (1.5 g) in MeOH (100 ml) was added NaBH4 (3 eq) in three portions at 0° C. The solution was then stirred for 3 h at rt and then concentrated in vacuo. The crude residue was taken up in EtOAc and washed with sat aq. NaHCO3, dried (MgSO4), and concentrated. The crude residue was purified by chromatography on silica gel (EtOAc/hex) to give the title compound as a pale yellow oil in 63% yield. MS (ESI) 317 (M+H).
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