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

Participants

Reaction Conditions

Reaction Steps

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.

Provenance & Evidence