Acetic Anhydride → (R)-2-((S)-2-acetamido-3-(1H-indol-3-yl)propanamido)-3-(tert-butyldisulfanyl)propanoic acid

Participants

Reaction Steps

A solution of (R)-2-((S)-2-amino-3-(1H-indol-3-yl)propanamido)-3-(tert-butyldisulfanyl)propanoic acid (H-Trp-Cys(StBu)-OH) (Compound SP639) (280 mg, 0.708 mmol) in methylene chloride (1.4 mL) was mixed with N-ethyldiisopropylamine (DIPEA) (371 μL, 2.12 mmol) and acetic anhydride (66.8 μL, 0.708 mmol) with stirring at room temperature, and the reaction solution was stirred at room temperature for 1 hour. The reaction solution was purified by reverse-phase silica gel column chromatography (0.1% aqueous formic acid solution/0.1% formic acid-acetonitrile solution) to afford (R)-2-((S)-2-acetamido-3-(1H-indol-3-yl)propanamido)-3-(tert-butyldisulfanyl)propanoic acid (Ac-Trp-Cys(StBu)-OH) (Compound SP640) (270 mg, 0.617 mmol, 87%).

Provenance & Evidence