反应详情

To a solution of O-benzyl-N-benzyloxycarbonyl-L-serine (1 g) and benzyl N-trifluoroacetyl-L-serinate (873 mg) in methylene chloride (20 ml) was added N,N-diethylaminopropyl-N'-ethylcarbodiimide hydrochloride (573 mg) and -N,N-dimethylaminopyridine (37 mg) at 0° C. The reaction mixture was allowed to warm to room temperature and stirred for an hour at room temperature. The reaction mixture was diluted with ethyl acetate (200 ml) and washed successively with 0.2N hydrochloric acid, water, 10% aqueous sodium hydrogen carbonate, water and brine. After drying over sodium sulfate, the ethyl acetate extract was filtered and concentrated. The residue was chromatographed on silica gel eluting successively with a 1:1 mixture of methylene chloride and hexane, methylene chloride, a 50:1 mixture of methylene chloride and acetone to give benzyl O-(O-benzyl-N-benzyloxycarbonyl-L-serinyl)-N-trifluoroacetyl-I,-serinate (1.5 g).

1. customat 0° C
2. washwashed successively with 0.2N hydrochloric acid, water, 10% aqueous sodium hydrogen carbonate, water and brine
3. dry with materialAfter drying over sodium sulfate
4. extractionthe ethyl acetate extract
5. filtrationwas filtered
6. concentrationconcentrated
7. customThe residue was chromatographed on silica gel eluting successively with a 1:1 mixture of methylene chloride and hexane, methylene chloride
8. additiona 50:1 mixture of methylene chloride and acetone
9. customto give benzyl O-(O-benzyl-N-benzyloxycarbonyl-L-serinyl)-N-trifluoroacetyl-I