Reaktion #5253

Reaktionsgleichung

product

3-methylthiomethyl-7-[2-(2 -tritylamino-4-thiazolyl)-2-methoxyimino-acetamido]-ceph-3-eme-4-carboxylic acid

trifluoroacetic acid

→

3-methylthiomethyl-7-[2-(2-amino-4-thiazolyl)-2-methoxyimino-acetamido]-ceph-3-eme-4-carboxylic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethe mixture was evaporated under reduced pressure at 30° C. to a volume of 15 ml
2. 2
   workup.ADDITION150 ml of ispropyl ether were added at 10° C. to the mixture which
3. 3
   workup.STIRRINGwas then stirred at 20° C. for 15 minutes
4. 4
   Filtrationfiltered
5. 5
   SonstigeThe 3.2 g of raw product were chromatographed over silica gel
6. 6
   Waschenwere eluted with aqueous 2M sodium chloride solution
7. 7
   workup.ADDITIONcontaining 4% of 1M sodium bicarbonate solution
8. 8
   workup.DISSOLUTIONThe raw product was dissolved in a mixture of 10 ml of eluant, 1.4 ml of aqueous 1M sodium bicarbonate solution, 1 ml of triethylamine and 1 ml of aqueous saturated sodium chloride solution
9. 9
   workup.ADDITIONthe solution was acidified to a pH of 3 by addition of 50% aqueous formic acid
10. 10
    Filtrationfiltered
11. 11
    Waschenthe product was washed with water

Vorschrift

A mixture of 6.15 g of the product of Step A and 61 ml of trifluoroacetic acid was stirred at 20° C. for 20 minutes and the mixture was evaporated under reduced pressure at 30° C. to a volume of 15 ml. 150 ml of ispropyl ether were added at 10° C. to the mixture which was then stirred at 20° C. for 15 minutes and was vacuum filtered. The 3.2 g of raw product were chromatographed over silica gel and were eluted with aqueous 2M sodium chloride solution containing 4% of 1M sodium bicarbonate solution. The raw product was dissolved in a mixture of 10 ml of eluant, 1.4 ml of aqueous 1M sodium bicarbonate solution, 1 ml of triethylamine and 1 ml of aqueous saturated sodium chloride solution and the solution was acidified to a pH of 3 by addition of 50% aqueous formic acid. The mixture was vacuum filtered and the product was washed with water and then with ether to obtain 0.99 g of syn isomer of 3-methylthiomethyl-7-[2-(2-amino-4-thiazolyl)-2-methoxyimino-acetamido]-ceph-3-eme-4-carboxylic acid.

Quelle