4-Piperidinecarboxylic acid → 1-Carbobenzoxy-4-piperidinecarboxylic Acid

Participants

Reaction Steps

In a 1-L round-bottom flask with a stir bar and equipped with an additional funnel was charged isonipecotic acid (13 g, 0.1 mol) followed by 1,4-dioxane (50 mL). The resulting stirred white suspension was added 5N NaOH aqueous solution (30 mL, 0.15 mol) at room temperature and the overall almost homogeneous solution was cooled in an ice-water bath. CbzCl (19 mL, 0.13 mol) was dropped from an additional funnel slowly in 15 min and the overall heterogeneous mixture was stirred at room temperature for 3.5 h. The resulting mixture was diluted with water (20 mL) and ethyl acetate (100 mL) and the separated aqueous layer was extracted with ethyl acetate (50 mL×2). The combined organic layers were washed with brine, dried over MgSO4, and concentrated to give the N-Cbz isonipecotic acid 3 as a colorless oil which was carried through to the next step without further purification. MS (ES+): 264 (M+H)+.

Provenance & Evidence