反应详情

A solution of trichloroacetyl isocyanate (1.32 g.) in dry acetone (5 ml.) was added dropwise to a solution of sodium 7-[2-(2-formamido-5-bromothiazol-4-yl)-2-methoxyiminoacetamido]-3-hydroxymethyl-3-cephem-4-carboxylate (1.9 g.) in dry dimethylformamide at -30° C. and stirred at -40° to -20° C. for 3.5 hrs. Water (20 ml.) was added dropwise to the reaction mixture below -20° C. and the mixture was poured into water (180 ml.). The mixture was adjusted to pH 2 with 6N-hydrochloric acid and extracted with ethyl acetate. The extract was washed with water, dried over magnesium sulfate and evaporated in vacuo. The residue was washed with diethyl ether and dried to give 7-[2-(2-formamido-5-bromothiazol-4-yl)-2-methoxyiminoacetamido]-3-trichloroacetylcarbamoyloxymethyl-3-cephem-4-carboxylic acid (syn isomer, 1.9 g.).

1. extractionextracted with ethyl acetate
2. washThe extract was washed with water
3. dry with materialdried over magnesium sulfate
4. customevaporated in vacuo
5. washThe residue was washed with diethyl ether
6. customdried