Acetone → (4S)-4-{[(tert-butoxy)carbonyl]amino}-5-methylhexanoic acid

Participants

Reaction Steps

A 2 L, one-necked flask (equipped with a magnetic stir bar and a nitrogen inlet) was charged with (S)-2-isopropyl-5-oxo-pyrrolidine-1-carboxylic acid, tert-butyl ester prepared in Step C above (77.4 g, 0.341 mol) and acetone (260 mL). To this solution was added 1M aqueous sodium hydroxide (408 mL, 0.408 mol), and the reaction mixture was stirred 30 minutes. The acetone was removed in vacuo and the resulting aqueous slurry was acidified, with vigorous stirring, by addition of solid sodium bisulfate (55 g, 0.45 mol) and diluted to 1 L with deionized water. The slurry was stirred for 2 h and the resulting white solid was collected by filtration, washed with deionized water, and dried in a vacuum oven to yield the product as a white solid.

Provenance & Evidence