Diphosgene → (2S,3S)-N-(4-acetyl-thiazol-2-yl)-2-[(R)-4-(4-methoxy-phenyl)-2,5-dioxo-imidazolidin-1-yl]-3-phenyl-butyramide

Participants

Reaction Conditions

Reaction Steps

(2S,3S)-N-(4-Acetyl-thiazol-2-yl)-2-[(R)-2-amino-2-(4-methoxy-phenyl)-acetylamino]-3-phenyl-butyramide (2.7 g, 90% purity, 5.2 mmol) and diisopropylethylamine (4.2 mL, 23.6 mmol) in tetrahydrofuran (50 mL) were added to a solution of diphosgene (0.48 mL, 4 mmol) in a mixture of toluene (50 mL) and tetrahydrofuran (50 mL) over 10 minutes at 0° C. The mixture was stirred at 0° C. for 20 minutes and diluted with ethyl acetate. The mixture was washed with water, brine and dried (sodium sulfate). Evaporation of the solvents and chromatography of the residue over silica gel with 0.4-1% v/v methanol in dichloromethane gave (2S,3S)-N-(4-acetyl-thiazol-2-yl)-2-[(R)-4-(4-methoxy-phenyl)-2,5-dioxo-imidazolidin-1-yl]-3-phenyl-butyramide (2.36 g, 92%) as a white solid.

Provenance & Evidence