Trifluoroacetic acid → 7-(4-Bromo-2-methoxyiminoacetoacetamido)-3-vinyl-3-cephem-4-carboxylic acid

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Reaction Steps

To a solution of benzhydryl 7-(4-bromo-3,3-diethoxy-2-methoxyiminobutyramido)-3-vinyl-3-cephem-4-carboxylate (syn isomer) (3.36 g) and anisole (2.1 g) in methylene chloride (20 ml) was added trifluoroacetic acid (8.0 g) under ice-cooling with stirring, and the stirring was continued at ambient temperature for an hour. After removal of the solvent, the residue was dissolved in a mixture of ethyl acetate and water. To the separated ethyl acetate solution was added water, followed by adjusting to pH 7 with a saturated aqueous sodium bicarbonate. To the separated aqueous solution was added ethyl acetate, followed by adjusting to pH 2 with 10% hydrochloric acid. The ethyl acetate layer was separated out, washed with an aqueous sodium chloride and then dried over anhydrous magnesium sulfate. Removal of the solvent gave 7-(4-bromo-2-methoxyiminoacetoacetamido)-3-vinyl-3-cephem-4-carboxylic acid (syn isomer) (1.6 g).

Provenance & Evidence