反应详情

1 g of the raw product of Step A of Example 1 was added under nitrogen to a mixture of 5 ml of dimethylformamide and 0.5 ml of methyl isocyanate at 5° C. and 0.5 ml of methyl isocyanate was added thereto. After 30 minutes at 5° C., another 0.5 ml of methyl isocyanate was added and after stirring 2 hours at room temperature, the mixture was poured into 75 ml of an aqueous 6% NaHCO3 solution. The mixture was extracted with ethyl acetate and the extracts were washed with sodium bicarbonate solution. The combined aqueous phases were added to ethyl acetate and the mixture was acidified with 6 N hydrochloric acid to a pH of 2. The mixture was decanted and the aqueous phase was extracted with ethyl acetate. The organic extracts were washed with water, dried and concentrated to dryness and the residue was empasted with isopropyl ether and was vacuum filtered. The product was taken up with methylene chloride and the solution was treated with activated carbon and was vacuum filtered. The filtrate was evaporated to dryness and the residue was crystallized from isopropyl ether to obtain 331 mg of 3-methylcarbamoyloxymethyl-7β-[2-(2-tritylamino-4-thiazolyl)-acetamido]-ceph-3-eme-4-carboxylic acid melting at about 210° C. Thin layer chromatography: Rf=0.42 (80-15-5-ethyl acetate-acetic acid-water).

1. extractionThe mixture was extracted with ethyl acetate
2. washthe extracts were washed with sodium bicarbonate solution
3. additionThe combined aqueous phases were added to ethyl acetate
4. customThe mixture was decanted
5. extractionthe aqueous phase was extracted with ethyl acetate
6. washThe organic extracts were washed with water
7. customdried
8. concentrationconcentrated to dryness
9. filtrationfiltered
10. additionthe solution was treated with activated carbon
11. filtrationfiltered
12. customThe filtrate was evaporated to dryness
13. customthe residue was crystallized from isopropyl ether