Phosphorus oxychloride → 4-Nitrobenzyl 7-[2-(6-formamidopyridin-2-yl)-2-methoxyiminoacetamido]-3-cephem-4-carboxylate

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Reaction Steps

A mixture of N,N-dimethylformamide (3 ml.) and phosphoryl chloride (460 mg.) was stirred at 37° to 40° C. for 30 minutes. To the solution were added methylene chloride (3 ml.) and 2-(6-formamidopyridin-2-yl)-2-methoxyiminoacetic acid (669 mg.) at -20° to -25° C. and stirred at -10° to -15° C. for one hour. A solution of 4-nitrobenzyl 7-amino-3-cephem-4-carboxylate (670 mg.) and trimethylsilylacetamide (2 g.) in methylene chloride (200 ml.) was added to the above solution at -10° to -15° C., and then stirred at the same temperature for 30 minutes. After the solution was concentrated under reduced pressure, ethyl acetate and water were added to the residue. The ethyl acetate layer was separated, washed with an aqueous solution of sodium bicarbonate, water and a saturated aqueous solution of sodium chloride, dried over magnesium sulfate and then concentrated under reduced pressure. The residue was triturated with diethyl ether to give 4-nitrobenzyl 7-[2-(6-formamidopyridin-2-yl)-2-methoxyiminoacetamido]-3-cephem-4-carboxylate (730 mg.), mp. 195° to 200° C. (dec.).

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