反应详情

To a solution of O-benzyl-N-benzyloxycarbonyl-L-threonine (1.5 g), benzyl N-trifluoroacetyl-L-homoserinate (1.34 g) and 4-N,N-dimethylaminopyridine (48.8 mg) in methylene chloride (30 ml) was added N,N-diethylaminopropyl-N'-ethylcarbodiimide hydrochloride (840 mg) at 0° C. After stirring for an hour at room temperature, the reaction mixture was concentrated. The residue was dissolved in ethyl acetate and washed successively with 0.1N 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 and a 50:1 mixture of methylene chloride and acetone (50:1) to give benzyl O-(O-benzyl-N-benzyloxycarbonyl-L-threonyl)-N-trifluoroacetyl-L-homoserinate (1.6 g).

1. concentrationthe reaction mixture was concentrated
2. dissolutionThe residue was dissolved in ethyl acetate
3. washwashed successively with 0.1N 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, methylene chloride
9. additiona 50:1 mixture of methylene chloride and acetone (50:1)