[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][CH:11]([OH:14])[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].[H-].[Na+].Cl.Cl[C:19]1[CH:24]=[CH:23][CH:22]=[CH:21][N:20]=1>CN(C)C=O>[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][CH:11]([O:14][C:19]2[CH:24]=[CH:23][CH:22]=[CH:21][N:20]=2)[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:2])[CH3:3]1-t-Butoxycarbonyl-4-piperidinol (5.0 g 24.88 mmol) in dry dimethylformamide (60 ml) was treated with sodium hydride (60% 2.99 g 74.75 mmol) at room temperature under argon and then with 2-chloropyridine hydrochloride (4.1 g 27.33 mmol). Then mixture was heated at 80° C. overnight. After cooling the reaction was carefully quenched with water (5 ml) and then diluted with more water (20 ml) and extracted with ethyl acetate (30 ml). The organic solution was washed with sat. sodium bicarbonate, dried (MgSO4) and evaporated to give 1-t-butoxycarbonyl-4-(2-pyridoxy)piperidine (4.96 g 72%).
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