Trifluoroacetic acid → 7-[2-Carboxymethoxyimino-2-(1,2,4-thiadiazol-3-yl)acetamido]-3-cephem-4-carboxylic acid

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Reaction Steps

Trifluoroacetic acid (3.6 ml) was added to a suspension of 7-[2-tert-butoxycarbonylmethoxyimino-2-(1,2,4-thiadiazol-3-yl)acetamido]-3-cephem-4-carboxylic acid (syn isomer) (1.2 g) in anisole (1.2 ml), and the mixture was stirred for 2 hours at ambient temperature. The resultant solution was added dropwise to diisopropyl ether (100 ml) and the precipitates were collected by filtration. The precipitates were added to a mixture of water (50 ml) and ethyl acetate (50 ml) and adjusted to pH 6.5 with 5% aqueous sodium bicarbonate. The separated aqueous layer was adjusted to pH 2.5 with 10% hydrochloric acid and extracted with ethyl acetate. The extract was washed with water, dried over magnesium sulfate and then evaporated to give 7-[2-carboxymethoxyimino-2-(1,2,4-thiadiazol-3-yl)acetamido]-3-cephem-4-carboxylic acid (syn isomer) (0.5 g).

Provenance & Evidence