Phosphorus oxychloride → 7-[2-(2-Formamidothiazol-4-yl)-2-(2,2,2-trifluoroethyoxyimino)acetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid

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Reaction Steps

Vilsmeier reagent prepared from N,N-dimethyl formamide (0.2 g.) and phosphoryl chloride (0.42 g.) in a conventional manner was added to ethyl acetate (10 ml.), and then 2-(2-formamidothiazol-4-yl)-2-(2,2,2-trifluoroethoxyimino)acetic acid (syn isomer, 0.75 g.) was added to the solution under ice-cooling and stirred at the same temperature for 30 minutes. The solution was added to a solution of 7-amino-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (0.83 g.) and trimethylsilylacetamide (2.62 g.) in ethyl acetate (30 ml.) at -30° C., and stirred at the same temperature for 1.5 hours. After adding ethyl acetate (100 ml.) and water to the resultant solution, the ethyl acetate layer was separated. Water (100 ml.) was added to the ethyl acetate solution adjusted to pH 7.5 with saturated aqueous solution of sodium bicarbonate. The aqueous layer was separated and the ethyl acetate (150 ml.) was added thereto, and adjusted to pH 1.5 with hydrochloric acid. The ethyl acetate layer was separated, washed with saturated aqueous solution of sodium chloride, dried over magnesium sulfate, and concentrated in vacuo. The residue was triturated with diethyl ether to give 7-[2-(2-formamidothiazol-4-yl)-2-(2,2,2-trifluoroethyoxyimino)acetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer, 1.2 g.).

Provenance & Evidence