Ammonium Chloride → HCID 22864981, compound

Participants

Reaction Steps

To a solution of (2S,4R)-4-tert-butyldimethylsiloxy-N-tert-butoxycarbonyl-2-(2-methoxycarbonyl-1-oxoethyl)pyrrolidine (402 mg, 1.0 mmol) in methanol (2 ml) was added sodium borohydride (19 mg, 0.5 mmol) under a nitrogen atmosphere under cooling with ice. The mixture was stirred for 30 minutes at the same temperature. To this reaction solution was added saturated aqueous ammonium chloride (about 2 ml). This mixture was poured into ethyl acetate-water (50 ml--50 ml) for liquid separation. The organic layer was washed successively with 10% aqueous citric acid and saturated aqueous sodium chloride, and dried over anhydrous magnesium sulfate. The solvent was removed in vacuo. The residue was purified by silica gel column chromatography [Wakogel™ C-300, heptane-ethyl acetate (3:1)] to obtain (2S,4R)-4-tert-butyldimethylsiloxy-N-tert-butoxycarbonyl-2-[(1S)-2-methoxycarbonyl-1-hydroxyethyl]pyrrolidine (113 mg, yield: 28%, less polar compound) and (2S,4R)-4-tert-butyldimethylsiloxy-N-tert-butoxycarbonyl-2-[(1R)-2-methoxycarbonyl-1-hydroxyethyl]pyrrolidine (86 mg, yield: 21%, polar compound) and a mixture of the two (202 mg, yield: 50%, (1S)-form:(1R)-form=4:6).

Provenance & Evidence