反应详情

Cefuroxime (4.24 g) and powdered potassium carbonate (0.690 g) were stirred in anhydrous N,N-dimethylformamide (40 ml) till a solution was obtained. The solution was cooled to -3°, 2-methoxy-2-methylpropanoic acid 1-bromoethyl ester (2.50 g) was added and the solution was stirred for 1 hour. It was then partitioned between 2N hydrochloric acid (100 ml) and ethyl acetate (200 ml and 100 ml) and the combined organic layers were washed sequentially with 100 ml each of 2N hydrochloric acid (2×), water, saturated aqueous sodium bicarbonate, water (2×) and saturated brine, dried over magnesium sulphate and concentrated under reduced pressure to ca 20 ml. The solution was added slowly to petroleum ether (200 ml) and the resulting precipitate was filtered off, washed with petroleum ether and dried under vacuum to give the title ester (2.20 g); λmax (ethanol) 277.5 nm E11 342; νmax (CHBr3) 3520 and 3400 (NH and NH2), 1788 (β-lactam C=O), 1750 (ester C=O), 1732 (αβ unsaturated ester and carbamate C=O), and 1688 and 1514 cm-1 (amide C=O).

1. customwas obtained
2. temperatureThe solution was cooled to -3°
3. customIt was then partitioned between 2N hydrochloric acid (100 ml) and ethyl acetate (200 ml and 100 ml)
4. washthe combined organic layers were washed sequentially with 100 ml each of 2N hydrochloric acid (2×), water, saturated aqueous sodium bicarbonate, water (2×) and saturated brine
5. dry with materialdried over magnesium sulphate
6. concentrationconcentrated under reduced pressure to ca 20 ml
7. additionThe solution was added slowly to petroleum ether (200 ml)
8. filtrationthe resulting precipitate was filtered off
9. washwashed with petroleum ether
10. customdried under vacuum