Lithium hydroxide, monohydrate → 1-(3,3-Dimethylbutyl)piperidine-4-carboxylic acid

Lithium 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%).