反应详情

Acetic anhydride (5 ml), sodium acetate (0.61 g) and potassium acetate (0.73 g) were added a solution of 7-(2-methoxyimino-3-oxo-4,4-dibromobutyramido)-3-hydroxycepham-4-carboxylic acid (syn isomer, 5 g) in dry tetrahydrofuran (50 ml), and stirred at 28° to 29° C. for 4 hours. After hydrogen bromide (5 ml) was added to the resultant solution, tetrahydrofuran was removed under reduced pressure therefrom. To the residue was added water (30 ml) and ethyl acetate (100 ml). The organic layer was separated, washed with water and 30% aqueous solution of sodium bromide in turn, and then dried over anhydrous magnesium sulfate. The solution was treated with activated charcoal, and concentrated under reduced pressure, and then the residue was pulverized with diisopropyl ether. The precipitates were collected by filtration, washed with diisopropyl ether and dried to give 7-(2-methoxyimino-3-oxo-4,4-dibromobutyramido)-3-cephem-4-carboxylic acid (syn isomer, 2.85 g).

1. customwas removed under reduced pressure
2. additionTo the residue was added water (30 ml) and ethyl acetate (100 ml)
3. customThe organic layer was separated
4. washwashed with water and 30% aqueous solution of sodium bromide in turn
5. dry with materialdried over anhydrous magnesium sulfate
6. additionThe solution was treated with activated charcoal
7. concentrationconcentrated under reduced pressure
8. filtrationThe precipitates were collected by filtration
9. washwashed with diisopropyl ether
10. customdried