反应详情

8 g of raw product of Step A were added with stirring at room temperature to a solution of 8 g of trichloroacetyl isocyanate in 160 ml of dry methylene chloride and after stirring for 15 minutes, 1.6 liters of a solution of aqueous 6% sodium bicarbonate were added thereto. The mixture was stirred at room temperature overnight and was then extracted with ethyl acetate. The organic phase was removed and the aqueous phase was acidified with 6 N hydrochloric acid to a pH of 2 in the presence of ethyl acetate. The organic phase was washed with water, dried and concentrated under reduced pressure to 30 ml. The product was precipitated by addition of isopropyl ether and the mixture was filtered and dried to obtain 2.7 g of 3-carbamoyloxymethyl-7β-[2-(2-tritylamino-4-thiazolyl)-acetamido]-ceph-3-eme-4-carboxylic acid melting at about 200° C. with decomposition.

1. stirringThe mixture was stirred at room temperature overnight
2. extractionwas then extracted with ethyl acetate
3. customThe organic phase was removed
4. washThe organic phase was washed with water
5. customdried
6. concentrationconcentrated under reduced pressure to 30 ml
7. customThe product was precipitated by addition of isopropyl ether
8. filtrationthe mixture was filtered
9. customdried