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

Participants

Reaction Steps

A solution of (S)-2-((S)-2-amino-3-(1H-indol-3-yl)propanamido)-3-(tert-butyldisulfanyl)propanoic acid (H-Trp-D-Cys(StBu)-OH) (Compound SP643) (870 mg, 2.20 mmol) in methylene chloride (4.4 mL) was mixed with N-ethyldiisopropylamine (DIPEA) (1.15 mL, 6.60 mmol) and acetic anhydride (208 μL, 2.20 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 (S)-2-((S)-2-acetamido-3-(1H-indol-3-yl)propanamido)-3-(tert-butyldisulfanyl)propanoic acid (Ac-Trp-D-Cys(StBu)-OH) (Compound SP644) (960 mg, 2.20 mmol, 100%).

Provenance & Evidence