反应详情

A slurry of sodium cefuroxime (20 g) in dimethylacetamide (100 ml) was cooled to 14° and (RS) 1-acetoxyethyl bromide (10 ml) was added. The mixture was stirred at 14° for 45 minutes before anhydrous potassium carbonate (0.5 g) was added. After stirring for a further 45 minutes ethyl acetate (200 ml) and 3% sodium bicarbonate solution (200 ml) were added. The mixture was stirred at ambient temperature for 1 hour and the two phases were allowed to separate. The aqueous layer was washed with ethyl acetate (100 ml) and the two organic layers were then washed sequentially with M hydrochloric acid (100 ml) and 20% sodium chloride solution (30 ml). The combined organic layers were stirred with charcoal (2 g) for 30 minutes before filtration. The filtrate was concentrated in vacuo to 176 ml. Water (1.9 ml) was added to the concentrate which was run into stirred 60°-80° petrol (1.76 l) over 15 minutes. The precipitated product was filtered off and washed with a mixture of petrol (105 ml) and ethyl acetate (12 ml) followed by petrol (118 ml). Drying at 40° in vacuo gave cefuroxime axetil 17.9 g: Solvents (GLC), ethylacetate 1.6%, petrol 1.5%; impurities by HPLC 4.1% m/m, isomer ratio 1.06:1; E1 cm1 % (MeOH) 364. The infra-red spectrum in Nujol was typical of the amorphous material.

1. additionwas added
2. additionwere added
3. customto separate
4. washThe aqueous layer was washed with ethyl acetate (100 ml)
5. washthe two organic layers were then washed sequentially with M hydrochloric acid (100 ml) and 20% sodium chloride solution (30 ml)
6. stirringThe combined organic layers were stirred with charcoal (2 g) for 30 minutes before filtration
7. concentrationThe filtrate was concentrated in vacuo to 176 ml
8. additionWater (1.9 ml) was added to the
9. concentrationconcentrate which
10. stirringinto stirred 60°-80° petrol (1.76 l) over 15 minutes
11. filtrationThe precipitated product was filtered off
12. washwashed with a mixture of petrol (105 ml) and ethyl acetate (12 ml)
13. customDrying at 40° in vacuo