Trifluoroacetic acid → 7-[2-Carboxymethoxyimino-2-(1,2,4-thiadiazol-3-yl)acetamido]3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid

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Reaction Steps

Trifluoroacetic acid (12 ml) was added to a suspension of 7-[2-t-butoxycarbonylmethoxyimino-2-(1,2,4-thiadiazol-3-yl)acetamido]-3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (4 g) in methylene chloride (8 ml) and anisole (4 ml) at ambient temperature and the solution was stirred for 1.5 hours at the same temperature. To the resulting solution was added diisopropyl ether under stirring. The precipitates were collected by filtration, washed with diisopropyl ether. The precipitates were added to the mixture of ethyl acetate and water, and the mixture was adjusted to pH 7.5 with 20% aqueous solution of sodium carbonate. The separated aqueous layer was adjusted to pH 5.0 with 10% hydrochloric acid. The resulting solution was subjected to column chromatography on macroporous non-ionic adsorption resin "Diaion HP-20" (Trademark: prepared by Mitsubishi Chemical Industries Ltd.) and eluted with water. The fractions containing the object compound were adjusted to pH 2.0 with 10% hydrochloric acid. The precipitates were collected by filtration, washed with water and dried over phosphorus pentoxide in vacuo to give 7-[2-carboxymethoxyimino-2-(1,2,4-thiadiazol-3-yl)acetamido]3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (0.77 g).

Provenance & Evidence