Diisopropyl Ether → Sodium 7-[2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylate

Participants

Reaction Steps

Sodium 7-[2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylate (syn isomer) (2.9 g), which was prepared from 7-[2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylic acid and sodium bicarbonate in substantially the same manner as that of Example 78-(1), was dissolved in N,N-dimethylformamide (30 ml), and thereto was added dropwise a solution of iodomethyl pivalate (1.62 g) in N,N-dimethylformamide (5 ml) under ice-cooling with stirring, and the stirring was continued at the same temperature for 10 minutes. To the reaction mixture were added ethyl acetate (200 ml) and water (150 ml), followed by separating out the organic layer, which was washed with a saturated aqueous solution of sodium bicarbonate and an aqueous solution of sodium chloride, and then dried over anhydrous magnesium sulfate. Removal of the solvent gave an oil, which was pulverized with diisopropyl ether to obtain pivaloyloxymethyl 7-[2-(2-aminothiazol-4-yl)-2-methoxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylate (syn isomer) (2.1 g).

Provenance & Evidence