反应详情

In dichloromethane (50 ml) was dissolved 7β-phenylacetamido-3-hydroxymethyl-3-cephem-4-carboxylic acid triethylamine salt (4.49 g) and, at room temperature, triethylamine (0.51 g) and diketene (1.26 g) were added. The reaction was conducted for 2 hours, after which time the solvent was distilled off under reduced pressure. The residue was diluted with water and adjusted to pH 6.0. This aqueous solution was extracted twice with ethyl acetate, brought down to pH 2.0 with 4 N-HCl and extracted three times with ethyl acetate. The ethyl acetate solution was washed with a saturated aqueous solution of sodium chloride, treated with magnesium sulfate and filtered. The solvent was distilled off under reduced pressure and the residue was recrystallized from ethyl acetate-ether. The above procedure provided 7β-phenylacetamido-3-(3-oxobutyryloxy)methyl-3-cephem-4-carboxylic acid (4.16 g) (yield 96.3%).

1. distillationafter which time the solvent was distilled off under reduced pressure
2. additionThe residue was diluted with water
3. extractionThis aqueous solution was extracted twice with ethyl acetate
4. extractionextracted three times with ethyl acetate
5. washThe ethyl acetate solution was washed with a saturated aqueous solution of sodium chloride
6. additiontreated with magnesium sulfate
7. filtrationfiltered
8. distillationThe solvent was distilled off under reduced pressure
9. customthe residue was recrystallized from ethyl acetate-ether