4-Nitrobenzyl 7-[2-ethoxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetamido]-3-cephem-4-carboxylate → 7-[2-Ethoxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetamido]-3-cephem-4-carboxylic acid

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Reaction Steps

A mixture of 4-nitrobenzyl 7-[2-ethoxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetamido]-3-cephem-4-carboxylate (syn isomer) (5.0 g) and 10% palladium on carbon (2.5 g) in 70% aqueous tetrahydrofuran (75 ml) was stirred under hydrogen atmosphere for 3 hours at ambient temperature. The catalyst was removed by filtration and the filtrate was concentrated to third volume. The residue was extracted with ethyl acetate and transferred into an aqueous solution of sodium bicarbonate. The aqueous layer was acidified to pH 3 with 10% hydrochloric acid and extracted with ethyl acetate. The extract was dried over magnesium sulfate and concentrated to 10 ml under reduced pressure. The resultant precipitates were collected, washed with ethyl acetate and dried to give 7-[2-ethoxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetamido]-3-cephem-4-carboxylic acid (syn isomer) (1.33 g), mp. 190° to 195° C. (dec.).

Provenance & Evidence