Dimethyl Sulfoxide → HCID 66848206, compound

Participants

Reaction Steps

To a solution of oxalyl chloride (23.5 ml, 246 mmol) in dichloromethane (400 ml), which was cooled to −75° C., dimethyl sulfoxide (35 ml, 492 mmol) in dichloromethane (60 ml) was added in 20 minutes. After 30 minutes at −70° C., a solution of (2S,4R)-4-hydroxy-2-(4-nitro-benzoyloxymethyl)-pyrrolidine-1-carboxylic acid tert-butyl ester (intermediate 55, 45 g, 123 mmol) in dichloromethane (300 ml) was added dropwise. After 2 hours at −70° C., N,N-diisopropylethylamine (60 ml) was added in 10 minutes. After 25 minutes at −60° C. and 30 minutes at room temperature dichloromethane (200 ml) was added. The organic solvent was washed with 0.5N HCl (500 ml), water (500 ml) and brine (500 ml), dried (Na2SO4) and evaporated to obtain a crude that was purified by silica gel chromatography (petroleum ether/ethyl acetate from 5/1 to 3/1). (S)-2-(4-Nitro-benzoyloxymethyl)-4-oxo-pyrrolidine-1-carboxylic acid tert-butyl ester was obtained as white solid (28.5 g, yield: 70%).

Provenance & Evidence