反应详情

(R)-tert-butoxycarbonylamino-{4-[2-(methoxy)-ethoxy]-phenyl}-acetic acid (0.6 g, 1.84 mmol), 2-chloro-4,6-dimethoxy-1,3,5-triazine (0.32 g, 1.84 mmol) and N-methylmorpholine (0.19 g, 1.84 mmol) in anhydrous tetrahydrofuran (20 mL) were stirred at room temperature for 4 hours. Then a solution of 2-((S)-2-amino-3-phenyl-propionylamino)-thiazole-4-carboxylic acid methyl ester (0.56 g, 1.84 mmol) in tetrahydrofuran (10 mL) was added. The reaction mixture was stirred at room temperature for 20 hours. The mixture was filtered though a short pad of silica gel and the residual material eluted from the silica gel with ethyl acetate. The filtrate was concentrated. The residue was purified by chromatography over silica gel eluted with 1:1 ethyl acetate/hexanes to give 2-((S)-2-{2-tert-butoxycarbonylamino-2-[4-(2-methoxy-ethoxy)-phenyl]-acetylamino}-3-phenyl-propionylamino)-thiazole-4-carboxylic acid methyl ester as a mixture of two epimers (R/S=85:15) (0.21 g,

1. filtrationThe mixture was filtered though a short pad of silica gel
2. washthe residual material eluted from the silica gel with ethyl acetate
3. concentrationThe filtrate was concentrated
4. customThe residue was purified by chromatography over silica gel
5. washeluted with 1:1 ethyl acetate/hexanes