406212-51-9

161491-24-3

406212-51-9

General procedure for the synthesis of methyl N-Boc-4-hydroxypiperidine-3-carboxylate from tert-butyl 4-oxopiperidine-1-carboxylate-3-carboxylate: To a solution of tert-butyl 1-(1,3-piperidinedicarboxylate) in methanol (800 mL) of 3-oxo-1,3-piperidinedicarboxylic acid (134.0 g, 520.8 mmol) was added in batches at 0 °C NaBH4 (9.85 g, 260.4 mmol). The reaction mixture was stirred overnight and allowed to warm up naturally to room temperature. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was dissolved in ethyl acetate, washed with saturated brine, dried over anhydrous MgSO4, filtered and concentrated under reduced pressure to afford 3-tert-butyl 3-methyl-4-hydroxy-1,3-piperidinedicarboxylate (120.8 g, 90% yield), which could be used for the next reaction without further purification.