4-[1-[(2-methylpropan-2-yl)oxycarbonyl]piperidin-2-yl]butanoic acid

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1,1′-Carbonyldiimidazole (23.3 g, 143.7 mmol) was added to a solution of 4-(1-tert-butoxycarbonyl)piperidin-2-yl)butanoic acid (2) (26 g, 95.8 mmol) in methylene chloride. The reaction mixture was stirred at room temperature for 1 h. Methanol (19.4 ml, 479 mmol) was then added and the reaction mixture was stirred overnight. The complete reaction was checked by means of TLC. When the reaction was complete, the reaction mixture was washed 3× with sat. NH4Cl solution (aqueous) and 2× with sat. NaCl solution. The organic phase was dried over MgSO4, filtered and concentrated under reduced pressure to obtain tert-butyl 2-(4-methoxy-4-oxobutyl)piperidine-1-carboxylate (3) (25.67 g, 94%). the reaction mixture was stirred overnight The complete reaction the reaction mixture was washed 3× with sat. NH4Cl solution (aqueous) and 2× with sat. NaCl solution The organic phase was dried over MgSO4 filtered concentrated under reduced pressure