Imidazole → (R)-2-Benzyloxycarbonylamino-3-iodo-propionic acid methyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of triphenylphosphine (23.3 g, 0.890 mol) and imidazole (6.0 g, 0.89 mol) in DCM (100 mL) was cooled to 0° C. and iodide (22.6 g, 0.890 mol) was added in small portions over 0.5 h. The cooling bath was removed and the mixture was stirred for 0.5 h. After the mixture was re-cooled to 0° C., a solution of Cbz-L-Ser-OMe 15.0 g, 0.590 mol) in DCM (100 mL) was added dropwise. After the addition, the cooling bath was removed and the mixture was allowed to warm to ambient temperature and stirred for 1.5 h. The mixture was filtered and the filtrate was concentrated to remove most of the solvent. MTBE (400 mL) was added to the residue and the mixture was filtered to remove triphenylphosphine oxide. The filtrate was concentrated and the residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc=50:1 to 10:1) to afford (R)-methyl 2-(benzyloxycarbonylamino)-3-iodopropanoate (12.3 g, 57% yield) as a colorless solid.

Herkunft & Nachweise