反应详情

In dimethylformamide (20 ml) are dissolved 2,2,2-trichloroethyl 3-methyl-7-oxo-3-cephem-4-carboxylate (3.63 g) and methoxyamine hydrochloride (2.63 g), followed by addition of pyridine (0.83 g) and methylene chloride (70 ml). The mixture is refluxed in a Dean-Stark trap packed with Molecular Sieve 3A for 2 hours. The reaction mixture is concentrated under reduced pressure and the residue is dissolved in ethyl acetate. This solution is washed with water, 1 N-HCl and aqueous sodium chloride in the order mentioned, dried over magnesium sulfate and concentrated under reduced pressure. The residual oil is subjected to silica gel (35 g) column chromatography and elution is carried out with methylene chloride. By the above procedure is obtained 2,2,2-trichloroethyl 7-methoxyimino-3-methyl-3-cephem-4-carboxylate as as oil (3.66 g).

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. washThis solution is washed with water, 1 N-HCl and aqueous sodium chloride in the order
5. dry with materialdried over magnesium sulfate
6. concentrationconcentrated under reduced pressure
7. washThe residual oil is subjected to silica gel (35 g) column chromatography and elution