Sodium Carbonate → Tert-butyl 7-[2-(2-formamidothiazol-4-yl)-2-methoxyiminoacetamido]-3-methoxymethyl-3-cephem-4-carboxylate

Participants

Reaction Steps

tert-Butyl 7-amino-3-methoxymethyl-3-cephem-4-carboxylate tosylate (2.0 g) was dissolved in a mixture of acetone (40 ml) and a saturated aqueous solution of sodium bicarbonate (15 ml), and thereto was added dropwise a solution of the activated acid, which was prepared from 2-(2-formamidothiazol-4-yl)-2-methoxyiminoacetic acid (syn isomer) (1.06 g), phosphorus oxychloride (0.85 g) and N,N-dimethylformamide (0.41 g) in tetrahydrofuran (10 ml), at 0° to 5° C. over a period of 10 minutes. During the addition, the pH value of the reaction mixture was maintained at pH 7.0 to 7.5 with a saturated aqueous solution of sodium carbonate. After stirring for an hour, the reaction mixture was diluted with water (50 ml), followed by extracting twice with ethyl acetate. The combined extract was washed with 5% aqueous solution of sodium bicarbonate and water, dried and then evaporated to dryness under reduced pressure to give a residue, which was triturated with diethyl ether to obtain tert-butyl 7-[2-(2-formamidothiazol-4-yl)-2-methoxyiminoacetamido]-3-methoxymethyl-3-cephem-4-carboxylate (syn isomer) (1.14 g).

Provenance & Evidence