Sulfuric acid magnesium salt (1:1) → 3-nitrooxypropyl (2S)-1-[(2S)-2-[[(2S)-1-ethoxy-1-oxo-4-phenylbutan-2-yl]amino]propanoyl]pyrrolidine-2-carboxylate

Beteiligte Stoffe

Reaktionsschritte

To a suspension of 1,1-carbonylimidazole (22 g, 136 mmol) in EtOAc (150 mL) a solution of commercial N-[(1S)-1-(ethoxycarbonyl)-3-phenylpropyl]-L-alanine (20.2 g, 72.32 mmol) in EtOAc (100 mL) was added dropwise in 10 minutes. The resulting solution was stirred at room temperature for 1 hour then L-proline 3-nitrooxypropyl ester (28.8 g, 113 mmol) was added and the mixture was stirred for 16 hours. Then was treated with saturated NaHCO3 and brine. The organic layer was anhydrified with magnesium sulphate and concentrated. The residue was purified by flash chromatography (nHexane/EtOAc 4:6) affording N-[(1S)-1-(ethoxycarbonyl)-3-phenylpropyl]-L-alanyl-L-proline 3-nitrooxypropyl ester (14.2 g, 26%) as a pale yellow oil.

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