Acetic Acid → 1-(3-tert-Butoxycarbonylamino-benzyl)-piperidine-4-carboxylic acid ethyl ester

Beteiligte Stoffe

Reaktionsschritte

A mixture of (3-formyl-phenyl)-carbamic acid tert-butyl ester (Schadendorf T et al., Tetrahedron Letters (2007), 48(51), 9044-9047), (1 g, 4.52 mmol), ethyl isonipecotate (800 mg, 5.09 mmol) and TEA (0.7 mL, 5 mmol) in MeOH (50 mL) is treated with acetic acid (1.03 mL, 18 mmol) and stirred at RT for 2 h. Sodium cyanoborohydride (398 mg, 6.33 mmol) is added at once and the reaction mixture is stirred for 18 h at RT. Water (5 mL) is added to the mixture and the solvents are evaporated. The residue is partitioned between diethyl ether (50 mL) and aqueous 0.1N HCl (50 mL). The aqueous phase is separated, washed twice with diethyl ether (25 mL) and basified with 1N NaOH solution (10 mL). The aqueous phase is extracted three times with DCM (3×50 mL). The combined organic phases are dried over MgSO4 and evaporated. The title compound is obtained as a thick oil; LC-MS A: tR=0.71 min; [M+H]+=363.48.

Herkunft & Nachweise