p-Toluenesulfonic acid → 7-Amino-3vinyl-3-cephem-4-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a suspension of benzhydryl 7-amino-3-vinyl-3-cephem-4-carboxylate hydrochloride (48 g) in methanol (250 ml) and anisole (70 ml) was added p-toluenesulfonic acid (85 g), and the mixture was stirred at 50° C. for 2 hours. The reaction mixture was poured into 10% aqueous sodium carbonate (600 ml) and ethyl acetate (700 ml), followed by adjusting to pH 7.5 with 20% aqueous sodium carbonate. The separated aqueous solution was washed with ethyl acetate (500 ml) and then adjusted to pH 2.5 with conc. hydrochloric acid, followed by stirring under ice-cooling for an hour. The precipitated crystals were collected by filtration and washed with acetone to obtain 7-amino-3-vinyl-3-cephem-4-carboxylic acid (15.4 g), mp 200° to 230° C. (dec.).

Provenance & Evidence