反应详情

Acetic acid (8 ml) and zinc powder (6 g) were added under stirring and ice-cooling to a solution of 2,2,2-trichloroethyl 2-methyl-7-[2-(1,3,4-thiadiazol-2-ylthio)-acetamido]-3-cephem-4-carboxylate (4.65 g) in anhydrous dimethylformamide (30 ml), and the mixture was stirred for 1 hour at the same temperature. After the reaction, ethyl acetate (150 ml) was added to the reaction mixture. The insoluble material was filtered off, and the filtrate was washed with 5% hydrochloride acid saturated with sodium chloride, and then extracted with a sodium bicarbonate aqueous solution. The extract was acidified with 10% hydrochloric acid and extracted with ethyl acetate, after which the ethyl acetate layer was washed with a saturated sodium chloride aqueous solution and dried over magnesium sulfate. After the solvent was distilled off, the residue was recrystallized from a mixture of ethyl acetate and benzene to give 2-methyl-7-[2-(1,3,4-thiadiazol-2-ylthio)-acetamido]-3-cephem-4-carboxylic acid (1.5 g), mp 197° to 199° C.

1. stirringthe mixture was stirred for 1 hour at the same temperature
2. additionwas added to the reaction mixture
3. filtrationThe insoluble material was filtered off
4. washthe filtrate was washed with 5% hydrochloride acid saturated with sodium chloride
5. extractionextracted with a sodium bicarbonate aqueous solution
6. extractionextracted with ethyl acetate
7. washafter which the ethyl acetate layer was washed with a saturated sodium chloride aqueous solution
8. dry with materialdried over magnesium sulfate
9. distillationAfter the solvent was distilled off
10. customthe residue was recrystallized from a mixture of ethyl acetate and benzene