Citric Acid → Trans-1-(Tert-Butoxycarbonyl)-3-Phenylpiperidine-4-Carboxylic Acid

Participants

Reaction Conditions

Reaction Steps

To a solution of the compound (6.3 g) obtained in step 2 in ethanol (60 mL) was added tBuONa (3.63 g), and the mixture was stirred at 90° C. for 1 hr. The reaction mixture was cooled, 8N aqueous sodium hydroxide solution (60 mL) and water (60 mL) were added, and the mixture was stirred at 85° C. for 2 hr. The reaction mixture was cooled, and citric acid (51 g) was added. Ethanol was evaporated under reduced pressure, and the residue was extracted with ethyl acetate (200 mL). The organic layer was washed with water and dried, and the solvent was evaporated under reduced pressure. The residue was crystallized from ethyl acetate-IPE-hexane to give (3R*,4R*)-1-(tert-butoxycarbonyl)-3-phenylpiperidine-4-carboxylic acid (5.26 g, 91%) as a white powder.

Provenance & Evidence