Bromoacetonitrile → (S)-5-azido-2-tert-butoxycarbonylamino-4-tert-butyldisulfanyl-pentanoic acid cyanomethyl ester

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Reaction Steps

Bromoacetonitrile (62 μl, 0.911 mmol) and N,N-diisopropylethylamine (79 μl, 0.456 mmol) were added to a solution of (S)-5-azido-2-tert-butoxycarbonylamino-4-tert-butyldisulfanyl-pentanoic acid (Compound 40a) (115 mg, 0.304 mmol) in acetonitrile (1 ml), and the reaction solution was stirred at room temperature for 2 hours. The reaction mixture was extracted with ethyl acetate/saturated ammonium chloride, and the organic layer was washed with brine. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting residue was purified by normal-phase silica gel column chromatography (hexane/ethyl acetate) to afford (S)-5-azido-2-tert-butoxycarbonylamino-4-tert-butyldisulfanyl-pentanoic acid cyanomethyl ester (Compound 41) (120 mg, 95%).

Provenance & Evidence