Water → (S)-tert-butyl 2-((2-(4-bromophenyl)-2-oxoethyl)carbamoyl)pyrrolidine-1-carboxylate

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Reaction Steps

To a suspension of 2-amino-4′-bromoacetophenone hydrochloride 17 (5.0 g, 20.0 mmol) in DCM (150 mL) was added DIPEA (2.6 g, 20 mmol) at room temperature. After stirred for 10 minutes, the suspension became yellow solution. To another flask charged with a DCM (100 mL) solution of N-Boc-L-Proline (5.2 g, 24.0 mmol) was added HOBt.H2O (3.7 g, 24.0 mmol) at room temperature. EDC.HCl (4.6 g, 24.0 mmol) was added to the proline mixture and the mixture was continually stirred at room temperature for 30 minutes. The above-mentioned yellow solution was added to the proline mixture and stirred at room temperature overnight. The resulting mixture was filtered through Celite® to remove the precipitate. The filtrate was extracted with H2O/DCM, and the organic layer was washed with brine, dried over MgSO4, and filtered. After being concentrated under reduced pressure, the crude product was purified by column chromatography (ethyl acetate: n-hexane=2:5) to yield pure product 18a as a yellow gel (7.4 g).

Provenance & Evidence