O.[OH-].[Li+].C([O:6][C:7]([CH:9]1[CH2:14][CH2:13][N:12]([CH2:15][CH2:16][C:17]([CH3:20])([CH3:19])[CH3:18])[CH2:11][CH2:10]1)=[O:8])C>C1COCC1.O>[CH3:18][C:17]([CH3:20])([CH3:19])[CH2:16][CH2:15][N:12]1[CH2:13][CH2:14][CH:9]([C:7]([OH:8])=[O:6])[CH2:10][CH2:11]1Lithium hydroxide monohydrate (1.37 g, 32.6 mmol) was added to a solution of 1-(3,3-dimethyl-butyl)-piperidine-4-carboxylic acid ethyl ester from Example E15.1 (7.16 g, 29.7 mmol) in THF (50 ml) and water (5 ml). The mixture was stirred at room temperature for 18 h then concentrated in vacuo. The residue was purified by flash chromatography on silica gel through an isolute (eluant; 90% dichloromethane:9% methanol:1% acetic acid) to yield the title compound (5.51 g, 87%).
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