反应详情

Cefuroxime (1.697 g) and powdered potassium carbonate (276 mg) were stirred in anhydrous N,N-dimethylformamide (20 ml) at 22° for 1 hour and the resulting solution was cooled in an ice/salt bath to -8°. A solution of crude 2-methoxy-2-methylpropanoic acid iodomethyl ester (1.52 g) in anhydrous N,N-dimethylformamide (6 ml) was added and the solution was stirred for 35 mins. Water (75 ml) was added and the mixture was extracted with ethyl acetate (2×100 ml). The combined organic layers were washed successively with 50 ml each of 2N hydrochloric acid (3×), water, saturated aqueous sodium bicarbonate, water, 10% aqueous sodium metabisulphite, water (2×) and saturated brine, dried over magnesium sulphate and concentrated under vacuum to ca 10 ml. The solution was added dropwise to stirred petroleum ether (100 ml) to give a precipitate which was filtered off, washed with petroleum ether and dried under reduced pressure to give the title ester (1.532 g); λmax (ethanol 277) nm E11 323; νmax (CHBr3) 3520 and 3400 (NH and NH2), 1788 (β-lactam C=O); 1735 (ester and carbamate C=O) and 1685 and 1510 cm-1 (amide C=O).

1. temperaturethe resulting solution was cooled in an ice/salt bath to -8°
2. extractionthe mixture was extracted with ethyl acetate (2×100 ml)
3. washThe combined organic layers were washed successively with 50 ml each of 2N hydrochloric acid (3×), water, saturated aqueous sodium bicarbonate, water, 10% aqueous sodium metabisulphite, water (2×) and saturated brine
4. dry with materialdried over magnesium sulphate
5. concentrationconcentrated under vacuum to ca 10 ml
6. additionThe solution was added dropwise
7. stirringto stirred petroleum ether (100 ml)
8. customto give a precipitate which
9. filtrationwas filtered off
10. washwashed with petroleum ether
11. customdried under reduced pressure