1,8-Diazabicyclo(5.4.0)undec-7-ene → (R)-2-((S)-2-amino-3-(1H-indol-3-yl)propanamido)-3-(tert-butyldisulfanyl)propanoic acid

Participants

Reaction Steps

A solution of the prepared (R)-2-((S)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-3-(1H-indol-3-yl)propanamido)-3-(tert-butyldisulfanyl)propanoic acid (Fmoc-Trp-Cys(StBu)-OH) (Compound SP602) (500 mg, 0.809 mmol) in N,N-dimethylformamide (1.6 mL) was mixed with 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) (134 μL, 0.890 mmol) with stirring at room temperature, and the reaction solution was stirred at room temperature for 30 minutes. 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-amino-3-(1H-indol-3-yl)propanamido)-3-(tert-butyldisulfanyl)propanoic acid (H-Trp-Cys(StBu)-OH) (Compound SP639) (290 mg, 0.733 mmol, 91%).

Provenance & Evidence