Hydrochloride methanol → (3RS, 4SR)-1-benzyl-3-(4-chloro-phenyl)-piperidine-4-carboxylic acid methyl ester

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Reaction Conditions

Reaction Steps

In a 500 ml round bottom flask with a magnetic stirring bar 3 g (9 mmol) (3RS, 4SR)-1-benzyl-3-(4-chloro-phenyl)-piperidine-4-carboxylic acid (SM050/4A) were suspended in 100 ml methanol. 50 mL 1.25 N HCl/MeOH was added and the mixture was stirred over night at reflux (76° C.). Another 50 mL 1.25 N HCl/MeOH was added and the reaction mixture was continued to reflux for 24 h. The solvent was removed by evaporation and the brown residue was diluted with 200 mL Na2CO3 aq. sat. and 5 mL 4 N NaOH aq. The mixture was extracted with 3 portions of 200 mL ethyl acetate. The combined organic layers were washed with 150 mL brine, dried over Na2SO4, filtered and evaporated. The residue was purified by column chromatography on silica eluting with ethyl acetate/heptane to yield after evaporation of the product containing fractions 2.74 g (88%) of the title compound as light yellow viscous oil. MS (m/e): 344.2 [(M+H)+].

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