Hydrochloric Acid → 7beta-[2-Cyclopropyloxyimino-2-(2-formamidothiazol-4-yl)acetamido]-3-(5,6-dioxo-2-methyl-1,2,5,6-tetrahydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid

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Reaction Steps

To a solution of 7β-amino-3-(5,6-dioxo-2-methyl-1,2,5,6-tetrahydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (966 mg) and sodium bicarbonate (437 mg) in a mixture of tetrahydrofuran (10 ml) and water (10 ml) was dropwise added the activated acid solution, prepared from 2-cyclopropyloxyimino-2-(2-formamidothiazol-4-yl)acetic acid (syn isomer) (500 mg) according to a similar manner to that described in Example 1, with stirring and keeping pH 7.0 to 8.0 with saturated aqueous solution of sodium bicarbonate at 0° to 5° C. The mixture was stirred for 20 minutes at the same temperature. To the mixture was added ethyl acetate (40 ml) and the mixture was adjusted to pH 1.5 with 6N hydrochloric acid. The resulting insoluble material was filtered off. The organic layer was separated from the filtrate, dried over magnesium sulfate and concentrated in vacuo. The residue was triturated with diethyl ether to give 7β-[2-cyclopropyloxyimino-2 -(2-formamidothiazol-4-yl)acetamido]-3-(5,6-dioxo-2-methyl-1,2,5,6-tetrahydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (685 mg).

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