Diphosgene → 2-{(2S,3S)-2-[(R)-4-(4-acetylamino-phenyl)-2,5-dioxo-imidazolidin-1-yl]-3-phenyl-butyrylamino}-thiazole-4-carboxylic acid methyl ester

Crude 2-{(2S,3S)-2-[(R)-2-(4-acetylamino-phenyl)-2-amino-acetylamino]-3-phenyl-butyrylamino}-thiazole-4-carboxylic acid methyl ester (≈0.175 mmol) was dissolved in dichloromethane (10 mL) and diisopropylethyllamine (72 μL, 0.41 mmol) was added. The resulting mixture was added to an ice cooled solution of diphosgene (13 μL, 0.109 mmol) in dichloromethane (10 mL). The reaction mixture was stirred for 15 minutes, diluted with ethyl acetate (100 mL) and washed with 0.2M aqueous hydrochloric acid, saturated aqueous sodium bicarbonate, brine and dried over sodium sulfate. The solution was filtered and the solvent removed in vacu. The residue was purified by chromatography over silica gel gradient eluted from 50% to 100% ethyl acetate in hexanes to afford 2-{(2S,3S)-2-[(R)-4-(4-acetylamino-phenyl)-2,5-dioxo-imidazolidin-1-yl]-3-phenyl-butyrylamino}-thiazole-4-carboxylic acid methyl ester (70 mg, 74%).

1. additiondiisopropylethyllamine (72 μL, 0.41 mmol) was added
2. washwashed with 0.2M aqueous hydrochloric acid, saturated aqueous sodium bicarbonate, brine
3. dry with materialdried over sodium sulfate
4. filtrationThe solution was filtered
5. customthe solvent removed in vacu
6. customThe residue was purified by chromatography over silica gel gradient
7. washeluted from 50% to 100% ethyl acetate in hexanes

ORD record

ord-fa87f6b07db640eb8d0c883be6c9066d

Source dataset

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07427635B2