4-Methylmorpholine → Phthalimide

Participants

Reaction Steps

Part A BOC derivative (2.27 g, 4.567 mmol) was dissolved in dichloromethane (10 mL) and TFA (30 mL) and stirred at RT 2.5 hours. The TFA was removed by distillation under reduced pressure and by coevaporation with toluene to give the TFA salt of the amine. This and Z-D-phenylalanine (1.50 g, 5.02 mmol)were dissolved in DMF (20 mL) at RT. HOBT (680 mg, 5.02 mmol), WSC (965 mg, 5.02 mmol) and NMM (1.1 mL, 10 mmol) were added. The reaction was stirred for 16 h, partitioned between ethyl acetate (70 mL) and 10% KHSO4 (70 mL). The aqueous layer was extracted with ethyl acetate (2×70 mL), and the organic layers were combined. The combined organic layers were washed with saturated NaHCO3 (50 mL) and saturated NaCl (50 mL), dried over magnesium sulfate and concentrated in vacuo to provide a viscous oil. The crude material was purified by chromatography on silica gel. Elution with ethyl acetate:hexanes(1:1) followed by ethyl acetate gave title phthalimide, (2.43 g, 78%) as a viscous oil which was characterized by NMR.

Provenance & Evidence