反应详情

To a solution of sodium 7-[2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-3-cephem-4-carboxylate (syn-isomer, 4.0 g) in dimethylsulfoxide (40 ml) were added 1-bromoethyl propionate (1.8 g) and sodium iodide (0.18 g), and the mixture was stirred at room temperature for 30 minutes. The reaction mixture was poured into a mixture of cold water and ethyl acetate, and the organic layer was separated. The remaining aqueous layer was extracted with ethyl acetate. The extract and the organic layer were combined, washed with water and dried over magnesium sulfate. The solvent was then distilled off and the residue was subjected to column chromatography using silica gel (50 g), elution being carried out with a mixture of benzene and ethyl acetate (3:2, v/v). The fractions containing the desired product were combined and the solvent was distilled off to give 1-propionyloxyethyl 7-[2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-3-cephem-4-carboxylate (syn isomer, 0.83 g), mp 113°-116° C. (decompn.).

1. customthe organic layer was separated
2. extractionThe remaining aqueous layer was extracted with ethyl acetate
3. extractionThe extract
4. washwashed with water
5. dry with materialdried over magnesium sulfate
6. distillationThe solvent was then distilled off
7. washsilica gel (50 g), elution
8. additionbeing carried out with a mixture of benzene and ethyl acetate (3:2
9. additionThe fractions containing the desired product
10. distillationthe solvent was distilled off