Trifluoroacetic acid → (S)-4-(benzylthio)-4-oxo-2-(pent-4-enamido)butanoic acid

Participants

Reaction Steps

DIC (N,N′-diisopropylcarbodiimide) (2.41 ml, 15.5 mmol), DMAP (N,N-dimethylaminopyridine) (315 mg, 2.58 mmol) and phenylmethanethiol (1.82 ml, 15.5 mmol) were added to a solution of the mixed crude product A (2.51 g, 12.9 mmol) of (S)-4-(tert-butoxy)-4-oxo-3-(pent-4-enamido)butanoic acid (Compound 1b-I) and pent-4-enoic acid (1:0.8) in CH2Cl2 (35 ml), and the mixture was stirred at room temperature for 4 hours. TFA (21 ml) was then added to the reaction mixture, which was stirred at room temperature for 9.5 hours. The reaction mixture was then concentrated under reduced pressure, and the resulting residue was reverse-phase silica gel column chromatography (10 mM aqueous ammonium acetate solution/methanol=80/20→40/60) to afford (S)-4-(benzylthio)-4-oxo-2-(pent-4-enamido)butanoic acid (Compound 1f-ID) (1.65 g, 74%).

Provenance & Evidence