反应详情

0.78 g of dicyclohexylcarbodiimide was added to a solution of the dry acid of Step C in 30 ml of dry methylene chloride and the mixture was stirred for an hour at room temperature and was then vacuum filtered to remove dicyclohexyl urea formed. The filtrate was cooled to -10° C. and a solution of 1.01 g of 7-amino-cephalosporanic acid in 13 ml of methylene chloride and 0.9 ml of triethylamine was added. The temperature returned to room temperature and 1 ml of acetic acid was added thereto. The mixture was vacuum filtered and the filtrate was washed with aqueous hydrochloric acid, dried and concentrated to dryness. The residue was taken up in 10 ml of dioxane and 1 ml of water and 3 ml of a saturated sodium bicarbonate aqueous solution were added thereto. The mixture was stirred and vacuum filtered and the filtrate was washed and evaporated to dryness. The residue was taken up in methylene chloride and the solution was washed with 10 ml of water and 5 ml of N hydrochloric acid. The mixture was decanted and the organic phase was washed with water, dried and effloresced with ether to obtain 1.747 g of raw product. The latter was dissolved in ethyl acetate and was crystallized by addition of ether to obtain 1.255 g of pure 3-acetoxymethyl-7-[2-(2-tritylamino-4-thiazolyl)-2-methoxyiminoacetamido]-ceph-3-eme-4-carboxylic acid in the syn configuration.

1. filtrationvacuum filtered
2. customto remove dicyclohexyl urea
3. customformed
4. temperatureThe filtrate was cooled to -10° C.
5. customreturned to room temperature
6. filtrationfiltered
7. washthe filtrate was washed with aqueous hydrochloric acid
8. customdried
9. concentrationconcentrated to dryness
10. addition1 ml of water and 3 ml of a saturated sodium bicarbonate aqueous solution were added
11. stirringThe mixture was stirred
12. filtrationvacuum filtered
13. washthe filtrate was washed
14. customevaporated to dryness
15. washthe solution was washed with 10 ml of water and 5 ml of N hydrochloric acid
16. customThe mixture was decanted
17. washthe organic phase was washed with water
18. customdried
19. customto obtain 1.747 g of raw product
20. customwas crystallized by addition of ether