Dimethylformamide → N-hydroxy-1-[4-methoxybenzenesulfonyl]-pyrrolidine-2(S)-carboxamide

Participants

Reaction Steps

1-[4-Methoxybenzenesulfonyl]-pyrrolidine-2(R)-carboxylic acid (1.12 g, 3.93 mmol) is dissolved in methylene chloride (40.0 mL). To this solution is added oxalyl chloride (0.69 mL, 7.85 mmol) and dimethylformamide (0.30 mL, 3.93 mmol), and the reaction is stirred at room temperature for 30 minutes. Meanwhile, in a separate flask, hydroxylamine hydrochloride (1.1 g, 15.7 mmol) and triethylamine (3.3 mL, 23.5 mmol) are stirred in tetrahydrofuran (20.0 mL) and water (4.0 mL) at 0° C. for 15 minutes. After 30 minutes, the methylene chloride solution is added in one portion to the second flask, and the combined contents are stirred overnight as the flask gradually warms up to room temperature. The reaction is then diluted with acidic water (pH=~3), and extracted several times with ethyl acetate. The combined organic layers are dried (MgSO4), and the solvent is evaporated. The product is purified by silica gel chromatography (50% ethyl acetate/hexane) to give N-hydroxy-1-[4-methoxybenzenesulfonyl]-pyrrolidine-2(S)-carboxamide, m.p. 163.5°-165.5° C.

Provenance & Evidence