Thioglycolic Acid → (2R,4S)-4-acetylthio-2-{4-[2-(4-nitrobenzyloxycarbonyl)oxyethyl]-1-piperazinylcarbonyl}-1-(4-nitrobenzyloxycarbonyl)pyrrolidine

Participants

Reaction Steps

A solution of 0.73 g of diethyl azodicarboxylate in 2 ml of tetrahydrofuran was added dropwise, whilst ice-cooling, to a solution of 2.1 g of (2R,4R)-4-hydroxy-2-{4-[2-(4-nitrobenzyloxycarbonyl)oxyethyl]-1-piperazinylcarbonyl}-1-(4-nitrobenzyloxycarbonyl)pyrrolidine [prepared as described in step (i) above] and 1.1 g of triphenylphosphine in 14 ml of tetrahydrofuran, and the resulting mixture was stirred at the same temperature for 10 minutes. A solution of 0.32 g of mercaptoacetic acid in 2 ml of tetrahydrofuran was then added dropwise to the mixture, and the mixture was stirred at room temperature for 1 hour. At the end of this time, the solvent was removed by distillation under reduced pressure, and the resulting residue was purified by column chromatography through silica gel, using a 20:1 by volume mixture of ethyl acetate and methanol as the eluent, to give 1.2 g of (2R,4S)-4-acetylthio-2-{4-[2-(4-nitrobenzyloxycarbonyl)oxyethyl]-1-piperazinylcarbonyl}-1-(4-nitrobenzyloxycarbonyl)pyrrolidine as a colorless powder.

Provenance & Evidence