反应详情

A mixture of 753 mg of the product of Step B, 0.75 ml of 98% formic acid and 9.25 ml of 50% aqueous formic acid was stirred at 55°-60° C. for 12 minutes and the mixture was evaporated to dryness at a temperature not above 30° C. The residue was taken up in 5 ml of water and the mixture was vacuum filtered. The product was washed with water and then with isopropyl ether and dried. The 481 mg of product was chromatographed over silica gel and was eluted with a 1-1 acetone-methylene chloride mixture to obtain 211 mg of the pivaloyloxymethyl 3-azidomethyl-7-[2-(2-amino-4-thiazolyl)-2-hydroxyimino-acetamido]-ceph-3-eme-4-carboxylate.

1. customthe mixture was evaporated to dryness at a temperature not above 30° C
2. filtrationfiltered
3. washThe product was washed with water
4. dry with materialwith isopropyl ether and dried
5. customThe 481 mg of product was chromatographed over silica gel
6. washwas eluted with a 1-1 acetone-methylene chloride mixture