Trifluoroacetic acid → Benzyl (S)-1-((1S,2R,4R)-2-acetamido-4-aminocyclohexyl)-2-oxopyrrolidin-3-ylcarbamate

Participants

Reaction Steps

To a solution of tert-butyl (1R,3R,4S)-3-acetamido-4-((S)-3-(benzyloxycarbonylamino)-2-oxopyrrolidin-1-yl)cyclohexylcarbamate (100 g, 0.205 mol) in dichloromethane (400 ml) was added TFA (400 ml) at −20° C. The reaction solution was stirred at room temperature for 2 h. The solvent and most of TFA were removed under reduced pressure, and the residue was diluted with dichloromethane (2 L) and aqueous K2CO3 solution (2 L). The pH was adjusted to 10 with 1N HCl. The aqueous layer was extracted with dichloromethane (3×1 L). The combined organic layer was dried over Na2SO4, and concentrated to give benzyl (S)-1-((1S,2R,4R)-2-acetamido-4-aminocyclohexyl)-2-oxopyrrolidin-3-ylcarbamate as an oil (81 g, 100% yield). This amine was used directly in the next step without further purification.

Provenance & Evidence