Bromoacetonitrile → (S)-cyanomethyl 2-((tert-butoxycarbonyl)amino)-6-((R)-2-((tert-butoxycarbonyl)amino)-3-(tert-butyldisulfanyl)propanamido)hexanoate

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Reaction Steps

N,N-diisopropylethylamine (0.073 mL, 0.421 mmol) and subsequently bromoacetonitrile (0.080 mL, 1.15 mmol) were added to a solution of (S)-2-((tert-butoxycarbonyl)amino)-6-((R)-2-((tert-butoxycarbonyl)amino)-3-(tert-butyldisulfanyl)propanamido)hexanoic acid (Compound 52) (206 mg, 0.383 mmol) in acetonitrile (0.3 mL) at room temperature under a nitrogen atmosphere. The reaction mixture was stirred at the same temperature for 5 hours and then concentrated under reduced pressure, and the resulting crude product was purified by normal-phase silica gel column chromatography (hexane/ethyl acetate) to afford (S)-cyanomethyl 2-((tert-butoxycarbonyl)amino)-6-((R)-2-((tert-butoxycarbonyl)amino)-3-(tert-butyldisulfanyl)propanamido)hexanoate (Compound 53) (172.2 mg, 78%).

Provenance & Evidence