反应详情

In dimethylformamide (5 ml) are dissolved 2,2,2-trichloroethyl 3-methyl-7-oxo-3-cephem-4-carboxylate (691 mg) and hydroxylamine hydrochloride (139 mg), followed by addition of pyridine (162 μl) and methylene chloride (10 ml). The mixture is refluxed in a Dean-Stark trap packed with Molecular Sieve 3A for 45 minutes. The reaction mixture is concentrated under reduced pressure and the residue is dissolved in ethyl acetate. The resultant solution is washed with water and aqueous sodium chloride, dried over magnesium sulfate and concentrated under reduced pressure. The residual oil is subjected to silica gel (20 g) column chromatography and elution is carried out with 5-13% ethyl acetatehexane to give 2,2,2-trichloroethyl 7-hydroxyimino-3-methyl-3-cephem-4-carboxylate as an oil (570 mg).

1. temperatureThe mixture is refluxed in a Dean-Stark trap
2. concentrationThe reaction mixture is concentrated under reduced pressure
3. dissolutionthe residue is dissolved in ethyl acetate
4. washThe resultant solution is washed with water and aqueous sodium chloride
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated under reduced pressure
7. washThe residual oil is subjected to silica gel (20 g) column chromatography and elution