反应详情

To a solution of 4,5-dihydroxy-2-pyridinecarboxylic acid (3.1 g) and 1-hydroxybenzotriazole (4.0 g) in dimethyl sulfoxide (30 ml) was added N,N'-dicyclohexylcarbodiimide (6.2 g). After being stirred at room temperature for 1 hour, the reaction mixture was added to a solution of 7β-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetamido]-3-(1-methyl-1-piperazinio)methyl-3-cephem-4-carboxylate (syn isomer) (10.0 g) and N-trimethylsilylacetamide (3.0 g) in dimethyl sulfoxide (50 ml), and the stirring was continued for 30 minutes. The mixture was added dropwise to diisopropyl ether (1.5 l) and the resulting precipitate was collected by filtration, which was dissolved in an aqueous solution of sodium bicarbonate. After the insoluble material was filtered off, the filtrate was adjusted to pH 3.0 with 1N hydrochloric acid and subjected to column chromatography on "Diaion HP-20" with 5% aqueous isopropyl alcohol as an eluent. The eluate was lyophilized to give 7β-[2-(5-amino-1,2,4-thiadiazol-3-yl)-2-methoxyiminoacetamido]-3-[1-methyl-4-(4,5-dihydroxy-2-pyridylcarbonyl)-1-piperazinio]methyl-3-cephem-4-carboxylate (syn isomer) (0.5 g).

1. waitthe stirring was continued for 30 minutes
2. filtrationthe resulting precipitate was collected by filtration, which
3. dissolutionwas dissolved in an aqueous solution of sodium bicarbonate
4. filtrationAfter the insoluble material was filtered off