Acetic Anhydride → (S)-4-tert-butoxycarbonylamino-4-[4-(N-acetylhydroxycarbamimidoyl)-benzyl carbamoyl]-butyric acid benzyl ester

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Reaction Steps

A solution of compound R (14.8 g, 20.0 mmol) and acetic anhydride (5.7 ml, 60.0 mmol) in acetic acid (100 ml) was stirred at room temperature for 45 min, and then solvent was evaporated in vacuo. The resultant residue was dissolved in EtOAc (300 ml) and extracted with water (2×75 ml) and brine (75 ml). The organic layer was then dried over MgSO4, evaporated and dried in vacuo to provide compound S (9.58 g, 18.2 mmol) as yellowish solid. LC-MS [M+H] 527.6 (C27H34N4O7+H, calc: 527.9). Compound S was used without further purification.

Provenance & Evidence