反应详情

To a solution of O-benzyl-N-benzyloxycarbonyl-L-threonine (1.15 g), benzyl 3-hydroxypropionate (604 mg) and 4-N,N-dimethylaminopyridine (41 mg) in methylene chloride (20 ml) was added N,N-diethylaminopropyl-N'-ethylcarbodiimide hydrochloride (641 mg) at 0° C. The reaction mixture was allowed to warm to room temperature and stirred at room temperature for an hour. The reaction mixture was concentrated and the residue was diluted with ethyl acetate and washed successively with 0.1 N 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, methyl chloride and a 50:1 mixture of methylene chloride and acetone to give 2-benzyloxycarbonylethyl O-benzyl-N-benzyloxycarbonyl-L-threonine (1.1 g).

1. concentrationThe reaction mixture was concentrated
2. additionthe residue was diluted with ethyl acetate
3. washwashed successively with 0.1 N hydrochloric acid, water, 10% aqueous sodium hydrogen carbonate, water and brine
4. dry with materialAfter drying over sodium sulfate
5. extractionthe ethyl acetate extract
6. filtrationwas filtered
7. concentrationconcentrated
8. customThe residue was chromatographed on silica gel eluting successively with a 1:1 mixture of methylene chloride and hexane, methyl chloride
9. additiona 50:1 mixture of methylene chloride and acetone