Pyridine → 7-[2-(5-Amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetamido]-3-[3-pyridinio-1-propen-1-yl]-3-cephem-4-carboxylate

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Reaction Steps

A mixture 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), pyridine (158 mg, 2 mmoles) in dimethylsulfoxide (DMSO) (1 ml) was stirred for 1 hour at room temperature. To the mixture was added ethyl acetate (20 ml) to precipitate a solid (620 mg), which was added to formic acid (6 ml) containing sodium bisulfite (60 mg). The mixture was stirred for 30 minutes at 40° C. and concentrated to dryness. The residue was dissolved in H2O (40 ml) and some insolubles were removed. The aqueous solution was charged on a column of reverse phase (PrepPAK-500/C18, 100 ml) eluting with H2O (300 ml) and 5% aqueous CH3OH (800 ml), and the eluate was monitored by uv (254 nm) and HPLC. The fractions (5% aqueous CH3OH) containing the desired product were combined, concentrated to a small volume and lyophilized to yield 40 mg (8%) of the title compound (I-1B), melting at >200° C. (dec.).

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