Ethyl Acetate → 7-[2-(5-Amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetamido]-3-[3-(4-carbamoylpyridinio)-1-propenyl]-3-cephem-4-carboxylate

Beteiligte Stoffe

Reaktionsschritte

To a stirred solution of diphenylmethyl 7-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetamido]-3-(3-iodo-1-propen-1-yl)-3-cephem-4-carboxylate (IX-1) (E, 716 mg, 1 mmole) in dry DMSO (2 ml) was added isonicotinamide (244 mg, 2 mmoles). The mixture was stirred at room temperature for 1 hour and then poured into ethyl acetate (200 ml). The resulting precipitate was collected by filtration, washed well with ethyl acetate and dried. A stirred mixture of the quaternized material (400 mg) and sodium bisulfite (40 mg) in HCOOH (4 ml) was heated at 40°-50° C. for 1 hour, and evaporated to dryness under reduced pressure. The crude solid was dissolved in water (40 ml). After filtration of an insoluble material, the filtrate was chromatographed on a reverse phase column (packing of PrepPAK/C18, 100 ml) using water and 5%, 10%, 20% and 30% aqueous CH3OH as eluant. The fractions containing the desired compound were combined, evaporated and lyophilized to give 21 mg (3.8%) of the title compound (I-1H) (E) as a pale yellow powder. Mp. >180° C. (dec.).

Herkunft & Nachweise