Acetic Acid → (2S,5S)-5-(2-benzylamino-2-carboxyethyl)pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester

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Reaction Steps

2.2 g of di-tert-butyl (2S,5S)-5-(2-benzylamino-2-carbamoylethyl)pyrrolidine-1,2-dicarboxylate were dissolved in 20 ml of ethanol and 5 ml of water. 1.2 g of solid sodium hydroxide were added thereto. The solution was then boiled under reflux for 36 h. For workup, it was cooled to room temperature and neutralized with acetic acid, and the ethanol was removed in vacuo. The residue was diluted with 20 ml of water and adjusted to a pH of 3 with acetic acid. The mixture was extracted 3 times with 30 ml of 5:1 ethyl acetate/butanol each time. The organic phases were combined and concentrated in vacuo. The residue was chromatographed on silica gel.

Provenance & Evidence