Trifluoroacetic acid → 7-[2-(2-Formamidothiazol-4-yl)-2-methoxyiminoacetamido]-3-methoxymethyl-3-cephem-4-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a cold suspension of tert-butyl 7-[2-(2-formamidothiazol-4-yl)-2-methoxyiminoacetamido]-3-methoxymethyl-3-cephem-4-carboxylate (syn isomer) (1.0 g) in methylene chloride (20 ml) were added trifluoroacetic acid (4.4 g) and anisole (0.2 ml), and the mixture was gradually warmed at 40° C., followed by stirring at 10° C. for 3 hours. After evaporation of the reaction mixture, to the residue was added ethyl acetate (20 ml), followed by extracting with an aqueous solution of sodium bicarbonate. The resultant aqueous solution was adjusted to pH 2.0 with diluted hydrochloric acid and then extracted with ethyl acetate. The extract was washed with a saturated aqueous solution of sodium bicarbonate, water and an aqueous solution of sodium chloride in turn, dried and then evaporated to dryness under reduced pressure. The residue was stirred for 30 minutes in diethyl ether, and the remained substance was collected by filtration to give 7-[2-(2-formamidothiazol-4-yl)-2-methoxyiminoacetamido]-3-methoxymethyl-3-cephem-4-carboxylic acid (syn isomer) (0.56 g).

Provenance & Evidence