Methyl chloroformate → [(S)-1-(4-Chloro-phenyl)-ethyl]-(3-oxo-3-phenyl-propyl)-carbamic acid methyl ester

Beteiligte Stoffe

Reaktionsschritte

Methyl chloroformate (15.5 mL) dissolved in dichloromethane (100 mL) was added to a mixture of 3-[(S)-1-(4-chloro-phenyl)-ethylamino]-1-phenyl-propan-1-one (38.0 g) and Na2CO3 (23.5 g) in a mixture of dichloromethane (100 mL) and water (100 mL) at such a rate that the solution temperature maintains between 20 and 26° C. After complete addition, the solution was stirred at ambient temperature for an additional 30 min. Then, the organic phase was separated and the aqueous phase was extracted once with dichloromethane. The combined organic phases were washed with brine and dried (MgSO4). Then, silica gel (20 g) was added and the resulting mixture was stirred vigorously for 30 min. The silica gel was separated by filtration, washed with dichloromethane (200 mL), and the combined filtrate was concentrated under reduced pressure to give an oil. The oil was treated with iPr2O (150 mL) to precipitate the title compound that was separated by filtration, washed with petroleum ether (30 mL), and dried. The filtrate was concentrated and the residue was taken up in petroleum ether (60 mL). The precipitate formed after a while of stirring was separated by filtration, washed with petroleum ether (20 mL), dried, and combined with the precipitate obtained before.

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